Ultrasound diagnostic apparatus and a medical image-processing apparatus

ABSTRACT

An ultrasound diagnostic apparatus  1  comprises an ultrasonic probe  2  for transmitting the ultrasound while three-dimensionally scanning, and receiving ultrasound reflected from biological tissue, an image processor  5  (and a signal processor  4 ) for generating image data for an MPR image based on results received thereof, an information memory  6  for storing cross-sectional-position information D showing a cross-section of this MPR image, a display part  81 , and a controller  9 . The image processor  5  generates image data for the new MPR image for the relevant cross-sectional position, based on the cross-sectional position shown in the cross-sectional-position information D 1  obtained when the MPR image was obtained in the past and the received results obtained by the new three-dimensional scan performed with the ultrasonic probe  2 . The controller  9  causes the display part  81  to display the new MPR image.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to foreign application JP 2006-262864,filed Sep. 27, 2006, which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an ultrasound diagnostic apparatus anda medical image-processing apparatus. The ultrasound diagnosticapparatus is an apparatus that transmits ultrasound to the inside of asubject using an ultrasonic probe, and obtains medical images of thesubject based on waves reflected therefrom. The medical image-processingapparatus is an apparatus for processing medical images obtained by theultrasound diagnostic apparatus. In particular, the present inventionrelates to the art used for comparative evaluation of motor functions ofthe same biological tissue obtained at different timing.

2. Description of the Related Art

The ultrasound diagnostic apparatus has a merit whereby it is possibleto observe an image instantly by a simple operation such as theoperation of simply placing the ultrasonic probe in contact with a bodysurface. Thus, the ultrasound diagnostic apparatus has been widely usedto diagnose the shape and function of biological tissue. In recentyears, more attention is being paid to an evaluation of a motor functionof biological tissue, such as heart wall motion, and especially anevaluation of a three-dimensional motor function.

Additionally, the ultrasound diagnostic apparatus is used for obtainingimages of biological tissue at a plurality of times at different timing(time and days), comparing such images, and thereby observing the timeelapsed changes in condition of the biological tissue. A typical exampleof such a use includes stress echocardiography. Other than that, theultrasound diagnostic apparatus is used in observation of a clinicalcourse, preoperative/postoperative observation, and so on.

Stress echocardiography is an examination for evaluating the motorfunction of a heart by comparing an image obtained at a time when apatient is not subjected to stress such as motion or medication, with animage obtained at a time in which the patient is subjected to stress.There is also an examination for evaluating heart function by applyingstress in stages and comparing images of the respective phases (e.g.,refer to Japanese Unexamined Patent Application Publication No.2005-304757).

In stress echocardiography using two-dimensional images, images areobtained from multiple views (tomographic planes) for each phase of thestress. Examples of such images include views such as an apicalfour-chamber view, an apical two-chamber view, a long-axis view of theleft ventricle, and a short-axis view of the left ventricle.

Additionally, in recent years, stress echocardiography usingthree-dimensional images has been proposed. This method is to generate,at each phase of the stress, volume data by three-dimensionally scanningultrasound, and obtain a desired cross-sectional image by subjectingthis volume data to MPR (Multi-Planar Reconstruction).

However, regarding a conventional ultrasound diagnostic apparatus thefollowing problems are pointed out. Firstly, there has been a problem inwhich stress echocardiography using two-dimensional images needs tovariously change the way in which the ultrasonic probe is placed on thesubject in order to obtain multiple images as described above, resultingin a complicated and long-time examination.

Secondly, although an image of the short-axis viewal view of the leftventricle is suitable for the observation of heart wall motion, it ispossible in stress echocardiography using two-dimensional images, toobtain only short-axis tomographic images at the papillary muscle level,so that there has been a problem in which the condition of the leftventricle cannot be observed comprehensively.

Meanwhile, stress echocardiography using three-dimensional images is toobtain volume data at each phase to generate an MPR image and thusdesignate a cross-section that makes it possible to adequately observethe condition of the cardiac muscle. However, there has been a problemin which this operation is highly complicated and time consuming.

Additionally, because there has been no means for comparativeobservation by displaying both a past MPR image and a new MPR image, ithas been particularly troublesome and time consuming to match across-sectional position of a past MPR image with a cross-sectionalposition of a new MPR image.

Furthermore, in the comparative observation, it is preferable to observetomographic images at the same cross-section for each phase, but it hasbeen difficult to set the same cross-section for each phase in aconventional configuration.

Moreover, even in the case of three-dimensionally scanning ultrasound,it is still necessary to place the ultrasonic probe properly on thesubject in order to observe the condition of biological tissue. However,it is not possible to verify the manner of placement of the ultrasonicprobe until an image is displayed for viewing.

Therefore, it has been particularly troublesome and time consuming todetermine the manner of placement of an ultrasonic probe.

In addition, even in the case of observation of the clinical course,preoperative/postoperative observation, and the like, it has beendifficult to designate the same cross-section for each timing whentomographic images based on volume data obtained at different timingsare comparatively observed.

SUMMARY OF THE INVENTION

The present invention was made in order to solve the aforementionedproblems, and an object of the present invention is to provide anultrasound diagnostic apparatus and a medical image-processing apparatusthat are capable of easily obtaining tomographic images of the samecross section of biological tissue in an examination for observingtime-elapsed changes of the biological tissue.

Further, another object of the present invention is to provide anultrasound diagnostic apparatus and a medical image-processing apparatusthat are capable of making an examination for observing time-elapsedchanges of biological tissue simple and short-time.

In a first aspect of the present invention, an ultrasound diagnosticapparatus comprises: an ultrasonic probe configured to transmitultrasound while three-dimensionally scanning, and receive ultrasoundreflected by a biological tissue; an image data generator configured togenerate image data of a tomographic image of the biological tissuebased on reception results of ultrasound; a memory configured to storecross-sectional-position information showing a cross-section a positionof the tomographic image; a display part; and a controller configuredto: control the image data generator so as to, based on across-sectional position shown in cross-sectional-position informationobtained when image data of a tomographic image of the biological tissuehas been generated previously, and reception results of new ultrasound,generate image data of a new tomographic image in the relevantcross-sectional position; and cause the display part to display the newtomographic image.

According to the first aspect, it is possible to, based on across-sectional position shown in past cross-sectional-positioninformation and reception results of new ultrasound, generate anddisplay a new tomographic image in a past cross-sectional position.Consequently, it is possible to easily obtain a tomographic image of thesame cross section of a biological tissue, in an examination ofobserving time change of the biological tissue.

In a second aspect of the present invention, an ultrasound diagnosticapparatus comprises: an ultrasonic probe configured to transmitultrasound while scanning, and receive ultrasound reflected by abiological tissue; an image data generator configured to generate imagedata of a tomographic image of the biological tissue, based on receptionresults of ultrasound; a memory configured to store scanning position information showing a scanning position of ultrasound by the ultrasonicprobe; a display part; and a controller configured to: control theultrasonic probe at the time of generation of image data of a newtomographic image of the biological tissue so as to transmit ultrasoundto a scanning position shown in scanning position information obtainedat the time of past generation of image data of a tomographic image;control the image data generator so as to generate image data of a newtomographic image based on reception results of the ultrasound; andcause the display part to display the new tomographic image.

According to the second aspect, it is possible to transmit ultrasound toa scanning position shown in past scanning position information, andgenerate and display a new tomographic image based on reception resultsof this ultrasound. Consequently, it is possible to easily obtain atomographic image of the same cross section of a biological tissue, inan examination of observing time change of the biological tissue.Moreover, it is possible to simplify and shorten time for an examinationof observing time change of a biological tissue.

In a third aspect of the present invention, a medical image-processingapparatus comprising: an image data generator configured to generateimage data of an MPR image, based on volume data of a biological tissuegenerated by an ultrasound diagnostic apparatus; a memory configured tostore cross-sectional-position information showing a cross-sectionalposition of the MPR image; a display part; and a controller configuredto: control the image data generator so as to, based oncross-sectional-position information of an MPR image from volume datagenerated on a first date, and volume data generated on a second date,generate image data of an MPR image of the second date in across-sectional position shown in cross-sectional information of thefirst date; and cause the display part to display an MPR image of thesecond date.

According to the third aspect, it is possible to, based on across-sectional position shown in cross-sectional-position informationof a first date, and volume data of a second date, generate and displayan MPR image of the second time in the cross-sectional position of thefirst date. Consequently, it is possible to easily obtain a tomographicimage of the same cross section of a biological tissue, in anexamination of observing time change of the biological tissue. Moreover,it is possible to simplify and shorten time for an examination ofobserving time change of a biological tissue.

In a fifth aspect of the present invention, a medical image-processingapparatus that processes volume data generated by an ultrasounddiagnostic apparatus for each of a plurality of phases in a stressechocardiography examination of a biological tissue, comprising: animage data generator configured to generate image data of an MPR image,based on the volume data; a memory configured to storecross-sectional-position information showing a cross-sectional positionof the MPR image; a display part; and a controller configured to: in acase where a second phase examination is performed after a first phaseexamination, control the image data generator so as to, based oncross-sectional-position information obtained at the time of generationof image data of an MPR image of the first phase, and volume data ofeach of the first phase and the second phase, generate image data of anMPR image of each of the first phase and the second phase in across-sectional position shown in cross-sectional-position informationof the first phase; and cause the display part to display an MPR imageof the first phase and an MPR image of the second phase side by side.

According to the fifth aspect, it is possible to, based oncross-section-position in formation of a first phase, and volume data ofeach of the first phase and a second phase, generate an MPR image ofeach of the first phase and the second phase in a cross-sectionalposition of the first phase, and display these MPR images side by side.Consequently, it is possible to easily obtain a tomographic image of thesame cross section of a biological tissue, in a stress echocardiographyexamination of the biological tissue. Moreover, it is possible tosimplify and shorten time for a stress echocardiography examination.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram illustrating an example of theentire configuration for an embodiment of an ultrasound diagnosticapparatus according to the present invention.

FIG. 2A and FIG. 2B are schematic explanatory diagrams for explaining anexample of an ultrasonic scanning mode in an embodiment of an ultrasounddiagnostic apparatus according to the present invention.

FIG. 3 is a schematic explanatory diagram for explaining an example ofan ultrasonic scanning mode in an embodiment of an ultrasound diagnosticapparatus according to the present invention.

FIG. 4 is a flow chart illustrating an example of an operation mode inan embodiment of an ultrasound diagnostic apparatus according to thepresent invention.

FIG. 5 is a schematic diagram illustrating an example of a displayscreen that is displayed by an embodiment of an ultrasound diagnosticapparatus according to the present invention.

FIG. 6 is a schematic diagram illustrating an example of a displayscreen that is displayed by an embodiment of an ultrasound diagnosticapparatus according to the present invention.

FIG. 7 is a schematic diagram illustrating an example of a displayscreen that is displayed by an embodiment of an ultrasound diagnosticapparatus according to the present invention.

FIG. 8 is a schematic diagram illustrating an example of a displayscreen that is displayed by an embodiment of an ultrasound diagnosticapparatus according to the present invention.

FIG. 9 is a schematic block diagram illustrating an example of theentire configuration in a modification example for an embodiment of anultrasound diagnostic apparatus according to the present invention.

FIG. 10 is a schematic explanatory diagram for explaining animage-displaying mode in a modification example for an embodiment of anultrasound diagnostic apparatus according to the present invention.

FIG. 11A and FIG. 11B are schematic explanatory diagrams for explaininga setup process of a cross-sectional position in a modification examplefor an embodiment of an ultrasound diagnostic apparatus according to thepresent invention.

FIG. 12 is a schematic block diagram illustrating an example of theentire configuration for an embodiment of an ultrasound diagnosticapparatus according to the present invention.

FIG. 13 is a flowchart illustrating an example of an operation mode inan embodiment of an ultrasound diagnostic apparatus according to thepresent invention.

FIGS. 14A and 14B are schematic explanatory diagrams for explaining ascanning mode for a multi-plane scan of the ultrasound in an embodimentof an ultrasound diagnostic apparatus according to the presentinvention.

FIG. 15 is a schematic block diagram illustrating an example of theentire configuration for an embodiment of a medical image-processingapparatus according to the present invention.

FIG. 16 is a schematic explanatory diagram for explaining a modificationexample for an embodiment of an ultrasound diagnostic apparatus and amedical image-processing apparatus according to the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

An embodiment of an ultrasound diagnostic apparatus and a medicalimage-processing apparatus according to the present invention will bedescribed in detail with reference to drawings.

First Embodiment

FIG. 1 illustrates an example of the entire configuration for the firstembodiment of an ultrasound diagnostic apparatus according to thepresent invention. An ultrasound diagnostic apparatus 1 is an apparatusthat is used, for example, for obtaining an image showing the shape ofbiological tissue such as a heart and an image showing a blood flowcondition.

[Apparatus Configuration]

The ultrasound diagnostic apparatus 1 comprises a two-dimensionalultrasonic probe 2, a transceiver 3, a signal processor 4, an imageprocessor 5, an information memory 6, an image data memory 7, a userinterface 8, and a controller 9. Specific examples for each partcomposing the ultrasound diagnostic apparatus 1 will be described below.

User Interface and Controller

First, the user interface 8 and the controller 9 will be describedhereunder. A display part 81 and an operation part 82 are provided inthe user interface 8.

The display part 81 corresponds to an example of a “display part” in thepresent invention. The display part 81 is composed of any display devicesuch as an LCD (Liquid Crystal Display) and a CRT (Cathode Ray Tube).

The display part 81 displays various images such as an ultrasonic imageobtained by the ultrasound diagnostic apparatus 1. Additionally, thedisplay part 81 displays various kinds of information such as DICOM(Digital Imaging and Communications in Medicine) supplementalinformation about the image.

The operation part 82 is composed of any operational device or inputdevice, such as a mouse, a trackball, a joystick, a control panel and akeyboard. The operation part 82 is used as an example of an “operationpart” in the present invention.

The controller 9 comprises a microprocessor such as a CPU, and a storageunit such as a memory and a hard disk drive. The storage unit stores acontrol program 91 beforehand. The microprocessor operates based on thecontrol program 91, and thus causes the ultrasound diagnostic apparatus1 to execute operations that are characteristic of the presentinvention.

Thus, the controller 9 causes the display part 81 to display an imageand a screen. Additionally, the controller 9 causes the ultrasounddiagnostic apparatus 1 to execute an operation in response to a controlsignal transmitted from the operation part The controller 9 functions asan example of a “controller” for the present invention.

Two-Dimensional Ultrasonic Probe

The two-dimensional ultrasonic probe 2 (may simply be referred to as anultrasonic probe 2) is provided with a plurality of ultrasonictransducers. The plurality of ultrasonic transducers are arrangedtwo-dimensionally (e.g., in a matrix state (lattice-like state)) (anillustration thereof is omitted). The plurality of ultrasonictransducers are individually driven by the transceiver 3 to transmit theultrasound. Additionally, the plurality of ultrasonic transducersreceive the ultrasound reflected by the biological tissue.

FIGS. 2A, 2B and FIG. 3 illustrate an ultrasonic scanning mode performedby the two-dimensional ultrasonic probe 2. As shown in FIG. 2A, theultrasonic probe 2 scans an ultrasonic beam transmitted from thearrangement surface of the ultrasonic transducers in the main scanningdirection X. Thus, a two-dimensional scan plane P is formed in a radialpattern (in a fan shape). Additionally, the ultrasonic probe 2 scans theultrasound in the sub scanning direction Y that is orthogonal to themain scanning direction X, and thereby sequentially forms a plurality offan-shaped two-dimensional scan planes P1, P2, . . . and Pn, which arearranged in the sub scanning direction Y as shown in FIG. 2B. Asdescribed above, the ultrasonic probe 2 transmits whilethree-dimensionally scanning the ultrasound to form a three-dimensionalscanning range R shown in FIG. 3.

A cross-sectional position for a tomographic image (B-mode image)obtained by the ultrasound diagnostic apparatus is generally determinedby the relative position of the ultrasonic probe or the scanning originwith respect to the biological tissue. In other words, if the positionof the ultrasonic probe or scanning origin changes, the tomographicimage of the cross-sectional position corresponding thereto will beobtained.

Transceiver

The transceiver 3 comprises a transmission part for supplying anelectrical signal to the ultrasonic probe 2 and transmitting ultrasound.Additionally, the transceiver 3 comprises a receiving part for receivingecho signals (reception signals), which are outputted from theultrasonic probe 2 that has received a reflected wave of this ultrasound(both illustrations are omitted).

The transmission part of the transceiver 3 comprises aclock-signal-generating circuit, a transmission delay circuit, a pulsecircuit, etc., which are not shown in the figure. Theclock-signal-generating circuit generates a clock signal that determinesthe transmission timing and transmission frequency of the ultrasound.The transmission delay circuit performs transmission focus by imposing adelay when transmitting the ultrasound. The pulse circuit incorporatespulse generators, the number of which is equivalent to the number ofindividual channels corresponding to each ultrasonic transducer. Thatwill cause the pulse circuit to generate a drive pulse at a transmissiontiming at which the delay is imposed and then supply it to eachultrasonic transducer of the ultrasonic probe 2.

Furthermore, the receiving part of the transceiver 3 comprises apre-amplifier circuit, an A/D conversion circuit, and a receptiondelay/addition circuit, which are not shown in the figure. Thepre-amplifier circuit amplifies, for every reception channel, echosignals outputted from each transducer of the ultrasonic probe 2. TheA/D conversion circuit converts the amplified echo signals from A(analog) to D (digital). The reception delay/addition circuit appliesthe delay time necessary for determination of the reception tendency tothe A/D-converted echo signals, and performs addition. This additionprocess will emphasize a reflection component from the directionaccording to the reception tendency. In some cases, a signal after theaddition process may be referred to as “RF data (raw data).” Thetransceiver 3 inputs the RF data that has been obtained in this way intothe signal processor 4.

Signal Processor

The signal processor 4 visualizes the amplitude information of the echosignal, based on the RF data having been in putted from the transceiver3. The data generated by the signal processor 4 is transmitted to thecontroller 9 to be displayed on the display part 81 of the userinterface 8, or inputted into the image processor 5. The signalprocessor 4 mainly comprises a B-mode process or 41, a Doppler processor42, and a CFM processor 43.

(B-Mode Processor)

The B (Brightness) mode processor 41 generates B-mode ultrasound rasterdata, based on the RF data. In concrete, the B-mode processor 41performs a band-pass filter process on the RF data, detects an envelopeof the output signal thereof, and compresses this detected data by alogarithmic transformation. Thus, with respect to the respectivetwo-dimensional scan planes P1 to Pn, image data of the tomographicimage in which the signal strength is expressed by brightness isgenerated.

(Doppler Processor)

The Doppler processor 42 generates blood flow information by a pulseDoppler method (PW Doppler method), a continuous wave Doppler method (CWDoppler method) or the like. These methods are selectively applied, forexample, by operating the operation part 82 of the user interface 8.

In the pulse Doppler method, a shift of frequency of the ultrasound(Doppler shift frequency component) arising from the Doppler effectcaused by blood flow at a certain depth (distance from the ultrasonicprobe 2) is detected using a pulse wave. Thus, the pulse Doppler methodhas a good distance resolution, and therefore is preferably used fordepth measurement of tissue and blood flow for a specified site.

In a case where the pulse Doppler method is applied, the Dopplerprocessor 42 extracts, with respect to the RF data inputted from thetransceiver 3, the Doppler shift frequency component by performing aphase detection of the signals at a specified size of blood-flowobservation range. Additionally, the Doppler processor 42 performs FFT(Fast Fourier Transformation) and then generates data showing theDoppler frequency distribution that represents the blood velocity in theblood-flow observation range.

Meanwhile, in the case of the continuous wave Doppler method, signalssuperposed with the Doppler shift frequency components for all sites inthe transmission/reception direction of the ultrasound (radial directionin the two-dimensional scan plane P) are obtained using a continuouswave. These signals are signals that reflect all blood flow conditionsin the path of the ultrasound. The continuous wave Doppler method hasthe merit that the speed of the measurement is excellent.

In a case where the continuous Doppler method is applied, the Dopplerprocessor 42 extracts, with respect to the RF data that is inputted fromthe transceiver 3, the Doppler shift frequency component by performingphase detection on the signals received in a sample line of blood-flowobservation. Additionally, the Doppler processor 42 performs FFT (FastFourier Transformation) and then generates data showing a Dopplerfrequency distribution that represents the blood velocity in the sampleline.

(CFM Processor)

The CFM (Color Flow Mapping) processor 43 operates when a color flowmapping method is performed. The color flow mapping method is a methodfor displaying at real-time in a color format by superposing the bloodflow information of the biological tissue on a B-mode image having abinary format. Examples of the blood flow information include thevelocity, distribution, and strength of blood flow. The blood flowinformation is obtained as binary format information. It should be notedthat “real-time” allows for a time lag to the extent that the ultrasonicimage based on the ultrasonic scan can be obtained while the ultrasonicprobe 2 is placed on the subject.

The CFM processor 43 comprises a phase detection circuit, a MTI (MovingTarget Indication) filter, an autocorrelator, and a flow speed/varianceoperator. The CFM processor 43 separates a shape signal reflecting theshape of the biological tissue and a blood flow signal reflecting theblood flow, by means of a high-pass filter process (MTI filter process).Additionally, the CFM processor 43 calculates information such as thevelocity, distribution and strength of blood flow for a plurality ofpositions by performing an autocorrelation process. In some cases, theCFM processor 43 may perform a non-linear process to reduce the shapesignal.

Image Processor

The image processor 5 performs various kinds of image processing basedon data generated by the signal processor 4. For example, the imageprocessor 5 has a DSC (Digital Scan Converter). The DSC converts thedata synchronized with the ultrasonic scan having been generated by thesignal processor 4, into data used for display (TV scan mode data). Thisprocess is called a scan conversion process.

Additionally, the image processor 5 is provided with a volume datagenerator 51 and an MPR processor 52, which will be described below.

(Volume Data Generator)

The volume data generator 51 generates volume data (voxel data) byinterpolating the image data of two-dimensional scan planes P1 to Pngenerated by the B-mode processor 41. The volume data generator 51comprises, for example, a DSC and a microprocessor.

In the case of display of a quasi three-dimensional image based on thevolume data, the image processor 5 generates image data for display byperforming image-processing such as a volume rendering process and anMIP (Maximum Intensity Projection) process. The controller 9 causes thedisplay part 81 to display the quasi three-dimensional image based onthe image data for display.

(MPR Processor)

The MPR (Multi-Planar Reconstruction) processor 52 generates image datafor a tomographic image (an MPR image) in an arbitrary cross-sectionalposition of the biological tissue by converting a cross-section of thevolume data generated by the volume data generator 51. The MPR processor52 comprises, for example, a DSC and a microprocessor.

As described above, the signal processor 4 (the B-mode processor 41thereof) and the image processor 5 generate image data for thetomographic image (MPR image based on the volume data) of the biologicaltissue, based on the results (data outputted from the transceiver 3) ofthe ultrasound received by the ultrasonic probe 2. The signal processor4 and the image processor 5 correspond to an example of an “image datagenerator” in the present invention.

Information Memory

The information memory 6 stores cross-sectional-position information Dshowing the cross-sectional position of the MPR image. The informationmemory 6 corresponds to an example of a “storage part” in the presentinvention. The cross-sectional position indicated in thecross-sectional-position information D is expressed, for example, byusing a three-dimensional coordinate system defined in the volume data.

The cross-sectional-position information D is stored so as to beassociated with patient identification information such as a patient ID.The controller 9 is capable of searching the intendedcross-sectional-position information D by using the patientidentification information as a search key. Additionally, thecross-sectional-position information D is also associated withexamination date in formation showing the date (and time) of generationof the image data of the MPR image. The examination date information isused as a search key when the cross-sectional-position information D issearched based on the examination date.

The information memory 6 comprises a storage unit such as a memory and ahard disk drive. The microprocessor or the like (controller 9) performsa process of writing/reading data in/out of the information memory 6.

Image Data Memory

The image data memory 7 stores various kinds of image data such asvolume data V generated by the volume data generator 51 and the imagedata for the MPR image. Additionally, various data such as the DICOMsupplemental information for the image data is also stored in the imagedata memory 7.

The image data memory 7 comprises a comparatively high-capacity storageunit, examples of which are memory such as a DRAM (Dynamic Random AccessMemory) and a hard disk drive. The microprocessor or the like(controller 9) performs a process of writing/reading data in/out of theinformation memory 7.

[Usage]

An example of a usage of an ultrasound diagnostic apparatus 1 will bedescribed with reference to FIG. 4 to FIG. 7.

The usage for a case of stress echocardiography of a heart will bedescribed hereunder. Stress echo cardiography is an examination forobserving how the motion (function) of a cardiac muscle has changed bystress applied to the subject. Accordingly, as described above, withrespect to phases before and after stress is applied (or each phase ofthe stress), it is important to comparatively observe the same sectionof the cardiac muscle by obtaining images of the same cross-sectionalposition of the heart.

The usage for obtaining (almost) the same cross-sectional position ofthe heart in the case of examination in the resting phase andexamination in a stress phase will be described hereunder. The restingphase means a condition in which the subject is not subjected to stresssuch as motion or medication. The stress phase means a condition inwhich the subject is subjected to stress.

Examination in the Resting Phase

First, examination in the resting phase is performed. For that, acoupling medium such as an ultrasound jelly is applied to the bodysurface of the subject and the ultrasound-outputting surface of theultrasonic probe 2. Then, an ultrasonic three-dimensional scan isperformed with the ultrasonic probe 2 placed on the body surface locatedadjacent to an apex of the heart (S1). Such a manner of placement of theultrasonic probe 2 is called an apical approach.

The results received by the ultrasonic probe 2 are transmitted to theB-mode processor 41 through the transceiver 3. The B-mode processor 41generates image data for the tomographic image, based on data havingbeen inputted from the transceiver 3. Thus, the image data for thetomographic image in each of the two-dimensional scan planes P1, P2, . .. and Pn shown in FIG. 2B can be obtained.

The volume data generator 51 generates the volume data based on theimage data (S2). The volume data is stored, for example, in the imagedata memory 7.

Here, Steps S1 and S2 are repeated at specified time intervals. Thatenables the volume data to be obtained at specified time intervals(frame rate). The volume data stored in the image data memory 7 includesa plurality of sets of volume data obtained at the frame rate.

The MPR processor 52 generates image data for the MPR image based on thevolume data (S3). The controller 9 causes the display part 81 to displaythis MPR image (S4). In some cases, the image data of the MPR image canbe directly generated from data obtained by a three-dimensional scanshown in Step S1.

In Step S3, the MPR images at a plurality of different cross-sectionalpositions of the heart can be displayed. Additionally, because an apicalapproach using the three-dimensional ultrasound scan (volume scan) isperformed in this usage, it is possible (in principle) to obtain anddisplay the MPR image for an optional cross-sectional position of theheart. This makes it possible to display, for example, the MPR image fora short-axis view of the left ventricle that is optimum for evaluationof heart wall motion at any level (an arbitrary position (depth) in thedirection of connecting the apex and base).

In Steps S3 and S4, the MPR processor 52 sequentially generates imagedata for the MPR image in the specified cross-sectional position, basedon the volume data obtained at the specified frame rate, and further,the controller 9 causes the display part 81 to display, at the specifiedframe rate, the sequentially generated MPR images.

Here, a user specifies a desired cross-sectional position by operatingthe operation part 82 when needed. The MPR processor 52 generates imagedata for the MPR image in the cross-sectional position specified by theuser, based on the volume data obtained at the specified frame rate. Thecontroller 9 causes the display part 81 to display the sequentiallygenerated MPR images. This makes it possible to display, on the displaypart 81, a moving image (specified frame rate) of the MPR image for theheart in the cross-sectional position specified by the user.

FIG. 5 illustrates an example of a display mode of the MPR image in StepS4. A plurality of MPR images are displayed on a tomographic imagedisplay screen 1000. Five display ranges 1001 to 1005 are provided inthis tomographic image display screen 1000. An MPR image is displayed oneach of the display ranges 1001 to 1005.

The display ranges 1001, 1002 and 1003, which are arranged in thevertical direction of the screen, respectively display moving images G1,G2 and G3 of the MPR image for a short-axis view of the left ventricleat an apex level, a papillary muscle level and a base level.

Here, the cross-sectional position and the number of the MPR imagedisplayed on the tomographic image display screen 1000 are preferablyset so that sites (segments) recommended by ASE (American Society ofEchocardiography) are all included. Alternatively, in order to observethe heart in more detail than that, the MPR images in morecross-sectional positions can also be displayed by setting, for example,sixteen cross-sectional positions of the heart.

Additionally, on the tomographic image display screen 1000, in additionto the above MPR images G1 to G3, moving images G4 and G5 of the MPRimages of an apical four-chamber view and an apical two-chamber view arerespectively displayed in the display ranges 1004 and 1005.

The user can change each of the cross-sectional positions of the MPRimages displayed in each of the display ranges 1001 to 1005 by movingthe cross-sectional positions shown in an operation part 1006 ofchanging the cross-sectional position, which is displayed under thedisplay ranges 1004 and 1005 by means of the operation part 82. Theoperation is performed, for example, by dragging a plane in the figureshowing the cross-sectional positions to a desired cross-sectionalposition.

Additionally, the user causes the moving images of the cross-sectionalposition (in particular, moving images G1, G2 and G3 of a short-axisview of the left ventricle) in which the heart wall motion can beadequately observed to be displayed by adjusting the manner of placementof the ultrasonic probe 2 on the subject while observing the MPR imagesdisplayed on the tomographic image display screen 1000 (S5).

Upon displaying the moving images of the appropriate cross-sectionalposition, the user performs a predetermined operation for storing theimage data with the operation part 82 (S6). Examples of this operationinclude double-click of a mouse. Once this operation is performed, thecontroller 9 stores, in the image data memory 7, the volume data for thespecified frame rate that is the basis of the moving images as volumedata V1 for the resting phase (S7).

Instead of storing the volume data V1, it is possible to configure so asto store the image data for the moving images G1 to G5 of the MPRimages, which are respectively displayed in the display ranges 1001 to1005. Additionally, it is also possible to configure so as to store boththe volume data V1 and the image data for the moving images G1 to G5.

Furthermore, the controller 9 stores, in the information memory 6, thecross-sectional-position information D1 showing the appropriatecross-sectional position in the resting phase (S8). Thecross-sectional-position information D1 includes, for example, thecross-sectional positions of the moving images G1 to G5 of the MPRimages, which are displayed in the respective display ranges 1001 to1005. Each cross-sectional position is shown, for example, in thethree-dimensional coordinate system defined in the volume data V1. Thisis the end of the examination in the resting phase.

Examination in a Stress Phase

Subsequently, examination in the stress phase will be performed. Forthat, the user firstly causes the display part 81 to display a screenthat displays the MPR image of the stress phase, such as atomographic-image-comparing screen 2000 shown in FIG. 6 (S9).

The display ranges 2001 to 2004 are provided in thetomographic-image-comparing screen 2000. The display ranges 2001 to 2004display images of two different phases side by side. In FIG. 6, the MPRimages of the resting phase are respectively displayed in the displayranges 2001 and 2002, and the MPR images of the stress phase arerespectively displayed in the display ranges 2003 and 2004.

The controller 9 reads out the volume data V1 for the resting phasestored in Step S7 from the image data memory 7 and transmits to the MPRprocessor 52. Additionally, the controller 9 transmits, to the MPRprocessor 52, the cross-sectional-position information D1 stored in StepS8.

The MPR processor 52 generates image data of the MPR images of theresting phase, based on the volume data V1 and thecross-sectional-position information D1. The controller 9 causes thetomographic-image-comparing screen 2000 to display the MPR images of theresting phase, based on the generated image data (S10).

In the display ranges 2001 and 2002 shown in FIG. 6, the moving imagesG4 and G5 of the MPR image of an apical four-chamber view and an apicaltwo-chamber view are respectively displayed as an example of a displaymode. The displayed images are not necessarily moving images but may bestill images at a certain phase of a heartbeat.

Additionally, the MPR image based on the volume data V1 is displayed inthe above Step S10, but it is not limited to this. For example, in thecase of storing the image data for the MPR image in Step S7 anddisplaying this MPR image in Step S10, it is possible to display, forexample, the MPR image at the cross-sectional position specified by theuser selectively in the display ranges 2001 and 2002.

The user applies an ultrasound jelly or the like when needed in order toobtain the images of the heart to which the stress is applied, andplaces the ultrasonic probe 2 on the body surface located near an apexof the heart for performing the ultrasonic three-dimensional scan (S11).

The results received by the ultrasonic probe 2 are transmitted to theB-mode processor 41 through the transceiver 3, whereby image data forthe tomographic image is generated. Furthermore, the volume datagenerator 51 generates volume data based on these sets of image data forthe tomographic images (S12). Steps S11 and S12 are repeated atspecified time intervals in the same way as Steps S1 and S2. Thatenables the volume data to be obtained at specified frame rate.

The MPR processor 52 generates image data for the MPR images (in thiscase, an apical four-chamber view and an apical two-chamber view) in thecross-sectional positions shown in the cross-section information D1,based on the volume data and the cross-sectional-position information D1(S13). The controller 9 causes the tomographic-image-comparing screen2000 to display the MPR images of the apical four-chamber view and theapical two-chamber view (S14).

Consequently, as illustrated in FIG. 6, in the display ranges 2003 and2004 of the tomographic-image-comparing screen 2000, moving images G4′and G5′ for the MPR images of the apical four-chamber view and theapical two-chamber view in the stress phase are displayed at real timeat the specified frame rate. The MPR images G4′ and G5′ respectivelyhave cross-sectional positions matched with the cross-sectionalpositions of the MPR images G4 and G5 for the resting phase.

In FIG. 6, the display range 2001 and the display range 2003 are placedside by side, and the display range 2002 and the display range 2004 areplaced side by side.

The display range 2001 displays the MPR image (moving image) G4 of theapical four-chamber view in the resting phase, and the display range2003 displays the MPR image (moving image) G4′ of the apicalfour-chamber view in the stress phase. That enables the user to easilyperform a comparative observation of the MPR images G4 and G4′ of theapical four-chamber view, which are obtained in different phases.

Further, the display range 2002 displays the MPR image (moving image) G5of the apical two-chamber view in the resting phase, and the displayrange 2004 displays the MPR image (moving image) G5′ of the apicaltwo-chamber view in the stress phase. That enables the user to easilyperform a comparative observation of the MPR images G5 and G5′ of theapical two-chamber view, which are obtained in different phases.

Here, the user adjusts the manner of placement of the ultrasonic probe 2on the subject as needed so that the cross-sectional position of the MPRimage G4′ of the apical four-chamber view coincides with thecross-sectional position of the MPR image G4 of the apical four-chamberview (or so that the cross-sectional position of the MPR image G5′ ofthe apical two-chamber view coincides with the cross-sectional positionof the MPR image G5 of the apical two-chamber view). In other words, theuser adjusts the manner of placement of the ultrasonic probe 2 so thatthe MPR images having (almost) the same cross-sectional position can bedisplayed in the display range 2001 and 2003, while comparativeobservation the images displayed in the display ranges 2001 and 2003(S15).

As described above, once one cross-sectional position is matched, othercross-sectional positions (an apical two-chamber view, and a short-axisview of the left ventricle at an apex level, at a papillary musclelevel, and at a base level) are also matched. It is necessary at thismoment to keep the positional relation between two cross sections not tochange.

Once the cross-sectional position of the MPR image G4′ in the stressphase, which is real-time displayed, matches the cross-sectionalposition of the MPR image G4 in the resting phase, the user performs anoperation of requesting storage of the image data (S16). Once thisoperation is performed, the controller 9 stores, in the image datamemory 7, volume data V2 in the stress phase that is real-time generatedat the specified frame rate (S17).

Here, instead of storing the volume data V2, it is possible to configureso as to display the image data of the moving images G4′ and G5′ of theMPR images, which are respectively displayed in the display ranges 2003and 2004. Additionally, it is also possible to configure so as to storeboth the volume data V2 and the image data of the moving images G4′ andG5′.

Additionally, the controller 9 stores, in the information memory 6,cross-sectional-position information D2 showing the cross-sectionalposition of the MPR image in the stress phase (S18). Thecross-sectional-position information D2 includes, for example, thecross-sectional positions of the moving images G4′ and G5′ of the MPRimages, which are displayed in the display ranges 2003 and 2004. Thiscross-sectional position is shown, for example, in the three-dimensionalcoordinate system defined in the volume data V2.

If there is a next phase (e.g., higher-stress phase) (S19; Y), the abovesteps S11 to S18 will be repeated. In this next phase, the MPR image fora phase (e.g., the previous phase) other than the resting phase can bedisplayed with the MPR image for the next stress phase. Afterobservation for all phases are completed (S19; N), the examination inthe stress phase ends.

The number of examinations in the stress phase is accordingly determineddepending on the stress amount and the clinical condition of thebiological tissue intended for observation, etc. Additionally, thenumber of examinations in the stress phase can also be determinedbeforehand, or accordingly determined depending on the intermediateexamination results and the like.

In the stress phase examination as described above, the cross-sectionalpositions for the MPR images of the apical four-chamber view or theapical two-chamber view are matched in the different phases by referringto the tomographic-image-comparing screen 2000. However, other MPRimages, such as the MPR image of a short-axis view of the left ventriclecan also be used for matching the cross-sectional positions.

FIG. 7 is an example of a tomographic-image-comparing screen 3000 forcomparative observation of the MPR images of a short-axis view of theleft ventricle. The tomographic-image-comparing screen 3000 includesdisplay ranges 3001 to 3006, which display the MPR images.

The display ranges 3001 and 3004, which are placed side by side,respectively display the MPR images G1 and G1′ of the short-axis view ofthe left ventricle at an apex level in the resting phase and in thestress phase. That enables the user to easily perform a comparativeobservation of the MPR images G1 and G1′ of the short-axis view of theleft ventricle at an apex level in the resting phase and in the stressphase. The MPR image G1′ in the stress phase is generated from thevolume data V2 based on the cross-sectional-position information D1.That results in that the MPR image G1′ is an image for thecross-sectional position that matches the one of the MPR image G1 in theresting phase (the following are the same as above).

Similarly, the display ranges 3002 and 3005 respectively display the MPRimages G2 and G2′ for the short-axis view of the left ventricle at apapillary muscle level in the resting phase and in the stress phase.Additionally, the display ranges 3003 and 3006 respectively display theMPR images G3 and G3′ for the short-axis view of the left ventricle at abase level in the resting phase and in the stress phase. That enablesthe user to easily perform a comparative observation of the MPR imagesG1 and G1′ respectively for the short-axis view of the left ventricle ata papillary muscle level and at a base level in the resting phase and inthe stress phase.

As in Step S15, the user can ad just the manner of placement of theultrasonic probe 2 on the subject as needed so that the cross-sectionalposition of the MPR image G1′ at an apex level is the same as the MPRimage G1 (or so that the cross-sectional position of the MPR image G2′or G3′ at a papillary muscle level or at a base level is the same as theMPR image G2 or G3).

Additionally, phase switching operation parts 3010 and 3020 are providedin the tomographic-image-comparing screen 3000. The phase switchingoperation parts 3010 and 3020 are operated for displaying the MPR imagesobtained in different phases. Examples of the stress phase include nostress (resting phase; the condition in which stress such as a drug isnot applied), low stress (low dose; the condition in which stress suchas a drug is low), and high stress (high dose; the condition in whichstress such as a drug is high).

In the display condition shown in FIG. 7, once the user operates thephase switching operation part 3010 (clicks one of right and leftdirection arrows by mouse), the images displayed in the display ranges3001, 3002 and 3003 are respectively switched from the MPR images G1, G2and G3 in the resting phase into, for example, the MPR images G1′, G2′and G3′ for the low stress condition. This switching process of thedisplay image is performed by the controller 9 having received a signalfrom the user interface 8 (the following are the same as above).

Additionally, in the display condition shown in FIG. 7, once the useroperates the phase switching operation part 3020 (clicks one of rightand left direction arrows with mouse), the images displayed in thedisplay ranges 3004, 3005 and 3006 are respectively switched from theMPR images G1′, G2′ and G3′ in the low stress condition into, forexample, the MPR images G1″, G2″ and G3″ (not shown) in the high stresscondition.

In a case where the images of the same phase are displayed when thephase switching operation part 3010 or 3020 is operated and thedisplayed images are switched, images of different phases may bedisplayed by automatically switching the images displayed in the otherside of the display range.

[Actions and Advantageous Effects]

Actions and advantageous effects of the ultrasound diagnostic apparatus1 are described. When obtaining the image data for the tomographic image(MPR image) of biological tissue such as a heart, the ultrasounddiagnostic apparatus 1 stores, in the information memory 6, thecross-sectional-position information D (D1) showing the cross-sectionalposition of that tomographic image. Additionally, when obtaining theimage data for a new tomographic image of the biological tissue, theultrasound diagnostic apparatus 1 obtains the image data for newtomographic image corresponding to the cross-sectional position shown inthe cross-section location information D of the image data for thetomographic image having been obtained in the past and then displaysthis new tomographic image and the past tomographic image side by side.

In particular, in a case in which a stress echocardiography is performedby obtaining volume data from the three-dimensional ultrasonic scan, theultrasound diagnostic apparatus 1 operates, based on thecross-sectional-position information D for the MPR image stored by theexamination in the past phase, to display at real time the MPR image forthe cross-section corresponding to the MPR image for this past phase.

According to the ultrasound diagnostic apparatus 1, in the examinationfor observing the time-elapsed changes in biological tissue, it ispossible to automatically obtain the tomographic image for thecross-sectional position corresponding to the tomographic image observedin the past examination, and therefore easily obtain the tomographicimages in the same cross-sectional position of the biological tissue.Examples of such examination include a stress echocardiography, anobservation of the clinical course, a pre-treatment/post-treatmentobservation (periodical medical examination such as a prognosticfollow-up), and a preoperative/postoperative observation.

Additionally, according to the ultrasound diagnostic apparatus 1, thetomographic image obtained in the past examination can be placed side byside with the tomographic image obtained in new examination in acondition in which the mutual cross-sectional positions are matched,which makes it possible to comparatively observe these images easily.

Additionally, the user can match the cross-sectional position of the newtomographic image with the cross-sectional position of the pasttomographic image by simply adjusting the manner of placement of theultrasonic probe 2 as needed. This makes it possible to easily performan examination such as a stress echocardiography examination forobserving the time-elapsed changes in biological tissue. It is alsopossible to shorten the examination time.

Furthermore, according to the ultrasound diagnostic apparatus 1, aplurality of pairs of the past tomographic image and the new tomographicimage, which are matched with the cross-sectional position, can besimultaneously displayed as shown in FIG. 6 and FIG. 7. That enables theuser to perform a comprehensive diagnosis, while comparative observationof the images of various cross-sectional positions of the biologicaltissues.

MODIFICATION EXAMPLES

It is possible to modify the ultrasound diagnostic apparatus 1 asdescribed below.

Modification Example 1

In the above embodiment, the usage for the case of obtaining a new imageat real time has been described, but it is not limited to this. Forexample, the present invention can also be applied to a case ofcomparative observation (review) of the images obtained at a pluralityof different dates in the past (timing that is different in date ortime).

In the case of comparison of the images obtained at two different dates,the image obtained at the earlier date may be referred to as a “past”image, where as the image obtained at the later date may be referred toas a “new” image.

Now, a review of the examination for observing the time-elapsed changesin biological tissue, such as stress echocardiography, is performedusing, for example, a tomographic-image-comparing screen 4000 shown inFIG. 8. The tomographic-image-comparing screen 4000 includes displayranges 4001 to 4006 as in the case of the tomographic-image-comparingscreen 3000 of FIG. 7. Additionally, the tomographic-image-comparingscreen 4000 includes phase switching operation parts 4010 and 4020,which are similar to those in FIG. 7.

The display ranges 4001 and 4004 respectively display the MPR images G1and G1′ of a short-axis view of the left ventricle at an apex level inthe resting phase and in the stress phase. The MPR images G1 and G1′ aremutually matched in cross-sectional position, for example, in the sameway as shown in Step S15 of FIG. 4.

Additionally, the display ranges 4002 and 4005 respectively display theMPR images G2 and G2′ for a short-axis view of the left ventricle at apapillary muscle level in the resting phase and in the stress phase. TheMPR images G2 and G2′ are also mutually matched in the cross-sectionalposition.

The display ranges 4003 and 4006 respectively display the MPR images G3and G3′ for a short-axis view of the left ventricle at a base level inthe resting phase and the stress phase. The MPR images G3 and G3′ arealso mutually matched in cross-sectional position.

In a case in which the volume data for each MPR image is stored, theuser can adjust the cross-sectional position for the MPR image asneeded. This adjustment operation is performed, for example, byspecifying the MPR image intended for changing the cross-section througha click using a mouse, and further by dragging an operation part 4030for changing cross-sectional position.

Additionally, in a case where the volume data for each MPR image isstored, once a pair of MPR images (e.g., MPR images G1 and G1′) intendedfor a comparative observation are specified, and the operation part 4030for changing cross-sectional position is operated, it is possible tochange the cross-sectional positions of this pair of MPR images at onetime.

This case will be described more specifically. For example, when the MPRimages G1 and G1′ are specified, and a new cross-sectional position isset by the cross-sectional-position change operation part 4030, thecontroller 9 transmits the content of the setting of the newcross-sectional position to the MPR processor 52. This content of thesetting is information shown in a three-dimensional coordinate systemdefined in the volume data V1 and V2. Additionally, the controller 9reads out the volume data V1 and V2 from the memory 7, and transmitsthem to the MPR processor 52. The MPR processor 52 generates image datafor the MPR image of the new cross-sectional position, based on thevolume data V1. Additionally, the MPR processor 52 generates image datafor the MPR image of the new cross-sectional position, based on thevolume data V2. The controller 9 causes the display range 4001 todisplay the MPR image for the new cross-sectional position in theresting phase, as well as causes the display range 4002 to display theMPR image for the new cross-sectional position in the stress phase,based on the image data generated from the MPR processor 52.

In this modification example, the MPR images in two different phases aredisplayed side by side, but it is also possible to display side by sidethe MPR images in three or more phases. In this case, it is possible toconfigure so that such one-time change for the cross-sectional positionis performed at one time for the MPR images in all phases (a group ofthree or more MPR images intended for the comparison).

By enabling this one-time change of the cross-sectional position, theneed for individually setting the desired cross-sectional position foreach phase is eliminated, and therefore, it becomes possible toefficiently perform the reviewing operation in a shorter time.

Additionally, a polar map (may be referred to as a bull's eye) 4040 isdisplayed on the tomographic-image-comparing screen 4000. The polar map4040, in which a three-dimensional heart is projected on atwo-dimensional image, quantifies the motion state of a partial regionof the heart, and represents the result of the quantification using acolor distribution or numerical value. To quantify the motion state, itis possible to employ speckle tracking using MPR two-dimensional imagesor three-dimensional images.

Examples of the motion state of biological tissue (heart) represented bythe polar map 4040 include displacement of the heart wall anddisplacement velocity, torsional motion and torsional motion velocity,shortening and shortening velocity, and strain of motion of the heartwall and strain rate, and relative rotation gradient.

The polar map 4040 represents, for example, the difference in numericalvalues showing the motion state for each partial region with respect tothe MPR images of the two phases (in which the cross-sectional positionsare matched) displayed on the tomographic-image-comparing screen 4000.

A polar map 4040 displayed based on the MPR image G1 and G1′ will bedescribed hereunder. The controller 9 quantifies the motion state foreach partial region of each of the MPR images G1 and G1′ by using thesame method as the conventional one. Here, each partial region is shownin a three-dimensional coordinate system defined in the volume data V1and V2. Additionally, the controller 9, for example, subtracts thenumerical value of MPR image G1 from the numerical value of MPR imageG1′ with respect to each partial region. Then, the controller 9 displaysthe polar map 4040 in which this difference is represented by a color ora numerical value.

By using this polar map 4040, it is possible to quantitatively evaluatethe changes in motion state of the cross-sectional position in differentphases. This makes it possible to improve the reliability andeffectiveness of diagnosis.

It may also be possible to quantitatively evaluate changes in motionstate of the biological tissue by applying other methods. Examples ofthese methods include TDI (Tissue Doppler Imaging). TDI measures andtwo-dimensionally displays, in a color format, the velocity of motionexercised by a comparatively faster-moving biological tissue such as aheart wall.

According to the modification example described above, it is possible toautomatically display side by side, the tomographic images in the samecross-sectional position, which have been obtained at different dates.This makes it possible to easily perform a comparative observation ofthe images in a review of the examination for observing the time-elapsedchanges in biological tissue.

Because stress echocardiography examination for the heart is to observehow the motion of the cardiac muscle has changed according to thepresence and amount of stress, the time-elapsed comparisons (comparisonbetween phases) for the same cross-section of the heart is critical.

Modification Example 2

In the above embodiment, the case of real-time observation duringthree-dimensional scanning of the biological tissue with ultrasound hasbeen described, but the present invention can also be applied toobservation of biological tissue (heart) via an ECG-gated scan.

FIG. 9 illustrates a configuration example of an ultrasound diagnosticapparatus used for observation of biological tissue by ECG-gated scan.An ultrasound diagnostic apparatus 10 has a configuration in which anelectrocardiograph 11 is added to the abovementioned ultrasounddiagnostic apparatus 1.

The electrocardiograph 11 is a device for generating anelectrocardiogram (ECG) that records the time-elapsed changes inelectrical activities of the heart. The electrocardiogram providesinformation showing the time-elapsed changes in electrical activities ofthe heart. The electrocardiograph 11 has a plurality of electrodesattached to the body surface of the subject in the same manner asconventionally conducted. Further, the electrocardiograph 11 has acircuit for generating the electrocardiogram based on the time-elapsedchanges in potential difference detected by the plurality of electrodes.The electrocardiogram generated by the electrocardiograph 11 isdisplayed on the display part 81 by the controller 9. Theelectrocardiograph 11 functions as one example of an “electrocardiogramgenerator” in the present invention.

Additionally, the controller 9 obtains a period T of theelectrocardiogram inputted from the electrocardiograph 11. The period Tis obtained by detecting the interval between an R wave and an adjacentR wave (R-R interval), for example. Furthermore, the controller 9transmits, to the transceiver 3, a control signal according to theperiod T of the electrocardiogram.

The transceiver 3 drives the ultrasonic probe 2 based on this controlsignal to transmit the ultrasound. The ultrasonic probe 2 transmits theultrasound while scanning in a circulative manner a plurality of partialregions of the heart at every period T of the electrocardiogram.

For example, in a case where the heart is divided into a number k of thepartial regions Q1 to Qk (i=1 to k representing the order of scanning),the ultrasonic probe 2 operates so as to scan the partial region Q1during the first one period T, scan the partial region Q2 during thenext one period T . . . and, in this way, scan the last partial regionQk, and further, scan the first partial region Q1 during the next oneperiod T.

The result of reception of the reflected ultrasonic waves sequentiallyreceived by the ultrasonic probe 2 is transmitted to the B-modeprocessor 41 through the transceiver 3. The B-mode processor 41generates image data for the tomographic images based on thesequentially inputted reception results, and inputs them in the volumedata generator 51.

The volume data generator 51 sequentially generates the volume data Wifor each partial region Qi, based on the image d at a for thesequentially input tomographic images. Each volume data Wi is stored inthe image data memory 7 by the controller 9 (refer to FIG. 9).

Furthermore, the MPR processor 52 sequentially generates image data forthe MPR images of the partial regions Qi, based on the plurality of setsof volume data Wi. The cross-sectional position for this MPR image isset by, for example, a user. The cross-sectional position may beautomatically set based on cross-sectional-position information E(described later).

The controller 9 causes the display part 81 to sequentially display theMPR images corresponding to the partial regions Q1 to Qk, based on theimage data sequentially generated by the MPR processor 52. At thismoment, the controller 9 causes the MPR images corresponding to thepartial regions Q1 to Qk to be sequentially displayed in synchronizationwith, for example, the period T of the electrocardiogram.

An example of the display mode of the MPR image in a case where theheart is divided into four partial regions Q1 to Q4 will be describedwith reference to FIG. 10. The display range Q of the ultrasonic image(MPR image in a specified cross-sectional position) is divided into thedisplay ranges Q1′ to Q4′, which correspond to the four partial regionsQ1 to Q4.

The controller 9 causes the display range Q1′ to display the MPR imagebased on the volume data W1 corresponding to the partial region Q1. Whenthe next one period T is passed and the image data of the MPR imagebased on the volume data W2 corresponding to the partial region Q2 isgenerated, the controller 9 causes the display range Q2′ to display thisMPR image. When the next one period T is passed and the image data ofthe MPR image based on the volume data W3 corresponding to the partialregion Q3 is generated, the controller 9 causes the display range Q3′ todisplay this MPR image. When the next one period T is passed and theimage data of the MPR image based on the volume data W4 corresponding tothe partial region Q4 is generated, the controller 9 causes the displayrange Q4′ to display this MPR image.

When the period T is passed once again and the image data of the MPRimage based on the volume data W1 corresponding to the partial region Q1is generated, the controller 9 causes the display range Q1′ to display anew MPR image of the partial region Q1.

Thus, the controller 9 updates, in the circulative manner, the MPRimages of the partial regions Q1 to Q4, which are displayed in thedisplay ranges Q1′ to Q4′, at every one period T.

Another display mode will be described hereunder. In this display mode,displayed MPR images are updated every time interval (k×period T)according to the number k of the partial regions Qi. It will bedescribed in detail with reference to the FIG. 10. The controller 9updates, every four periods (=4T), all of the MPR images of the partialregions Q1 to Q4, which are generated every one period T.

This display mode will be described in more detail. As described above,four new MPR images corresponding to the partial regions Q1 to Q4 aregenerated at every four periods. For the four new images, the controller9 causes the MPR images of the partial region Q1, the partial region Q2,the partial region Q3 and the partial region Q4 to be displayed at onetime in the display range Q1′, the display range Q2′, the display rangeQ3′ and the display range Q4′, respectively. That enables four displayimages to be updated at every four periods.

In the case of imaging with ECG-gated scan, it is possible to employ adisplay mode other than described above.

Based on the above preparations, a process according to the presentinvention will be described As illustrated in FIG. 9, the ultrasounddiagnostic apparatus 10 stores the cross-sectional-position informationE showing the cross-sectional position of the MPR image obtained in thepast. Additionally, the ultrasound diagnostic apparatus 10 stores thevolume data W having been the basis of this MPR image. The volume data Wincludes the number k of volume data corresponding to the partialregions Q1 to Qk of the heart.

As in the above embodiment, it is possible to store the image data ofthe MPR image based on the volume data W instead of storing the volumedata W, or it is possible to store the image data of the MPR image basedon the volume data W together with the volume data W.

In a case where a new ultrasonic image of the relevant heart is obtainedusing the ECG-gated scan method, the controller 9 sets a partial regionof the heart intended for this-time examination, based on divisioninformation showing a division mode of the heart. The divisioninformation is stored, for example, in the information memory 6.

The division information may include, for example, information on thenumber k of partial regions, or information on the range for eachpartial region (e.g., a range for the ultrasonic scan, and a range fordisplay of an image). The controller 9 sets the partial region for theheart, based on the division information. Additionally, the controller 9sets a process of generating the image data by the volume data generator51 and the MPR processor 52, based on the division information.Additionally, the controller 9 sets the number of the display ranges fordisplaying the MPR images, based on the division information. Adescription will be made below assuming the number k of the partialregions is 4.

The controller 9 transmits the cross-sectional-position information Estored in the information memory 6 to the MPR processor 52. Then, theMPR processor 52 generates image data for the MPR image in thecross-sectional position shown in the cross-sectional-positioninformation E.

The display part 81 displays a cross-sectional image-comparing screenthat is the same as in FIG. 7, for example. Thiscross-sectional-image-comparing screen is provided with display rangesQ′ and R′ (not shown), which are the same as in FIG. 10. The displayrange Q′ displays the past MPR image. The display mode thereof is, forexample, the abovementioned one-time update performed at every fourperiod. Meanwhile, the display range R′ displays the MPR image obtainedby this-time examination in the same display mode (describe later).

Here, the past examination is assumed to be an examination in theresting phase for stress echocardiography, and this-time examination isassumed to be an examination in the stress phase. Accordingly, it isgeneral that the period T′ of the electrocardiogram for this-timeexamination is shorter than the period T for the examination in theresting phase or less stress phase (T′<T).

The controller 9 detects the period T′ based on the electrocardiograminputted from the electrocardiograph 11. The ultrasound diagnosticapparatus 10 performs processes of generating the volume data andgenerating the image data for the MPR image, in synchronization with theperiod T′. At this time, a new MPR image is generated so as to matchwith the cross-sectional position shown in the cross-sectional-positioninformation E for the past examination.

The controller 9 updates, at one time, the MPR images to be displayed inthe display range R′ at every four periods (=4T′). At this time, thecontroller 9 also updates, at one time, the past MPR images insynchronization with the four periods (=4T′) (in other words, one-timeupdates at every four periods (=4T′)). Thus, both the past MPR imagesand the new MPR images are displayed in synchronization with the periodT′ (period: display update interval=1:4).

It should be noted that the di splay mode for the past MPR images andthe new MPR images is not limited to the above. As an example thereof,in consideration with T′<T, display of the image range according to theratio between the period T and the period T′, can be omitted out of allthe past MPR images. For example, in the case of T′: T=1:2, the imagescorresponding to scan performed during the first half period T/2 aredisplayed in a circulative manner, in synchronization with the periodT′. At this time, the range for the scan performed during each period ofT and T′ is the same, but the number of obtained volume data isdifferent.

According to this modification example, it is possible to automaticallyobtain the tomographic image for the cross-sectional position so as tomatch with the tomographic image observed in the past examination, inthe examination conducted for observing the time-elapsed changes inbiological tissue by the ECG-gated scan method. Therefore, it ispossible to easily obtain the tomographic image for the samecross-sectional position of this biological tissue.

Additionally, since the tomographic image obtained in the pastexamination and the tomographic image obtained in the new examination,can be displayed side-by-side, these images can be easily compared. Inparticular, both the tomographic images are displayed in synchronizationwith the period of the electrocardiograph, whereby it is possible toeasily understand the condition of the heart in a desired phase of theheartbeat.

Additionally, the user can match the cross-sectional position of the newtomographic image with the cross-sectional position of the pasttomographic image by simply adjusting the manner of placement of theultrasonic probe 2 as needed. This makes it possible to easily performan examination for observing the time-elapsed changes in biologicaltissue. It is also possible to shorten the examination time.

Furthermore, according to this modification example, it is possible tosimultaneously display a plurality of pairs of the past tomographicimage and the new tomographic image, whose cross-sectional positions arematched with each other. That enables the user to perform acomprehensive diagnosis, while comparative observation of the images ofvarious cross-sectional positions of the biological tissues.

Modification Example 3

The ultrasound diagnostic apparatus according to this modificationexample functions so as to, when a imaging mode is changed, obtain thecross-section image for the cross-sectional position in accordance withthe new imaging mode.

Here, an imaging mode means a type of imaging that is set beforehandaccording to the difference in the biological tissues intended forobservation and the difference in the imaging methods. Examples of theimaging mode include a “stress echo mode” for performing a stressechocardiography examination of the heart, an “abdomen mode” forobserving the inside condition of the abdomen, and a “fetus mode” forobserving the condition of the fetus. The imaging mode may be called“protocol,” since each mode is provided with a program (protocol) to beused.

By setting the imaging mode, the ultrasound diagnostic apparatus scansthe ultrasound in the mode that is suitable for the object intended forobservation and the imaging method (a program used for scanningcontrol). Additionally, the ultrasound diagnostic apparatus performs aprocess of generating the image data in the mode that is suitable forthe object intended for observation and so on.

In order to set the imaging mode, the user interface 8 is used. Forthat, the controller 9, for example, causes the display part 81 todisplay the screen for setting the imaging mode. The user refers to thisscreen and specifies a desired imaging mode using the operation part 82.The controller 9 sets each part in the apparatus to the conditionaccording to the specified imaging mode.

An example of a process according to this embodiment will be describedhereunder. In this example, the case of performing an examination in theresting phase for stress echocardiography, subsequently performing anexamination for an abdomen and then back to performing an examination inthe stress phase for stress echo cardiography will be describedhereunder.

In stress echocardiography using, for example, the drug stress, suchexamination flow is employed for the case of performing anotherexamination (in this case, the examination for an abdomen) during theperiod until the drug starts working.

First, the cross-sectional-position information D showing thecross-sectional position of the MPR image obtained by the examination inthe resting phase is stored in the information memory 6. Additionally,volume data V1 obtained in this examination (and/or the image data forthe MPR image) is stored in the image data memory 7 (refer to FIG. 1).

Once the examination for the resting phase is completed, the userchanges the imaging mode into the abdomen mode by using the userinterface 8. Then, the user applies the ultrasound jelly to the abdomenof the subject and placing the ultrasonic probe 2 on the abdomen,thereby performing the examination.

Once the examination for the abdomen is completed, the user puts theimaging mode back to the stress echo mode by using the user interface 8,and starts the examination for the stress phase. The controller 9 causesthe display part 81 (display ranges 3001 to 3003 of thetomographic-image-comparing screen 3000) to display the MPR imagesobtained in the stress phase.

The controller 9 transmits the cross-sectional-position information D inthe examination for the resting phase to the MPR processor 52. Thus, theMPR images of the stress phase having the cross-sectional positionmatched with those of the MPR images of the resting phases are generatedbased on the reception results obtained in the 3-dimensional ultrasonicscan by the ultrasonic probe 2, and are displayed respectively in thedisplay ranges 3004 to 3006 of the tomographic-image-comparing screen3000.

The user matches the cross-sectional position of the MPR image for thestress phase, which is displayed in real-time, with the cross-sectionalposition of the MPR image for the resting phase, by adjusting the mannerof placement of the ultrasonic probe 2 as needed. Once thecross-sectional positions are matched, the user performs the specifiedoperation, and stores volume data V2 (and/or the image data for the MPRimage) for the stress phase.

According to this modification example, when the imaging mode ischanged, the cross-sectional position is automatically set in accordancewith the new imaging mode, so that it is possible to easily match thecross-section in an examination after the change. In particular, in thecase of performing another examination during an interval period betweenexaminations for observing the time-elapsed changes in biologicaltissue, it is possible to automatically obtain the tomographic image forthe cross-sectional position matched with that of the tomographic imageobserved before another examination, and therefore, it is possible toeasily obtain the tomographic images at the same cross-sectionalposition.

Additionally, since the tomographic image obtained before the otherexamination and the tomographic image obtained after the otherexamination are displayed side-by-side, these images can be easilycomparatively observed.

Additionally, the user can match the cross-sectional position of thetomographic image after the other examination with the cross-sectionalposition of the tomographic image before the other examination by simplyadjusting the manner of placement of the ultrasonic probe 2 as needed.This makes it possible to easily perform an examination for observingthe time-elapsed changes in biological tissue. It is also possible toshorten the examination time.

Fourth Modification Example

This modification example is to perform a process based on ModificationExample 3 applying the cross-sectional position according to the changeof the imaging mode. In particular, a sub-mode is provided for eachphase in the stress echo mode.

Once the drug stress is applied, the size of the heart may becomesmaller than in the resting phase. In order to deal with suchphenomenon, for example, the following configuration can be made. First,it is configured so that a screen for selection of a phase is displayedon the display part 81 and a phase can be specified with the operationpart 82. In particular, it is configured so that the stress phase modecan be specified at the time of shift to the stress phase. In the caseof performing the examination for the stress phase in stages (e.g., lowstress phase and high stress phase, etc.), it is preferable that eachstress phase can be individually specified.

FIGS. 11A and 11B illustrate a change in size of a heart H between theresting phase and the stress phase. Here, the length from an apex to abase is considered as a size of the heart H. The length of the heart Hfor the resting phase is denoted by L. Additionally, the length of theheart H when the drug stress is applied is denoted by α×L (α<1). Thecontraction rate α for the heart H is a parameter that is dependent on aphase type and a drug type.

The contraction rate α can be clinically obtained like an average valueof the multiple clinical data. The contraction rate α is also obtainedfrom the results of the examination conducted to the relevant subject inthe past. The contraction rate a can be obtained by calculating L′/L(=α) in addition to measuring the length L based on the volume data V1obtained in the resting phase, and measuring the length L′ based on thevolume data V2 real-time obtained in the resting phase. It is desirableto calculate the contraction rate for each stress phase, in the case ofperforming the examination for the stress phase in stages.

It is assumed that in the resting phase, a cross-sectional position h1for a short-axis view of the left ventricle at an apex level, across-sectional position h2 for a short-axis view of the left ventricleat a papillary muscle level, and a cross-sectional position h3 for ashort-axis view of the left ventricle at a base level are individuallyset as shown in FIG. 11A. The respective cross-sectional positions h1,h2 and h3 are represented, for example, in a three-dimensionalcoordinate system defined in the volume data V1. These cross-sectionalpositions h1, h2 and h3 are stored as the cross-sectional-positioninformation D1 in the information memory 6.

Once the user specifies the stress phase, the controller 9 individuallycalculates the cross-sectional position h1′ for a short-axis view of theleft ventricle at the apex level, the cross-sectional position h2′ for ashort-axis view of the left ventricle at the papillary muscle level, andthe cross-sectional position h3′ for the short-axis view of the leftventricle at a base level, which are obtained in the stress phase, basedon the contraction rate α and the cross-sectional-position informationD1.

An example of the calculating process for obtaining the cross-sectionalpositions h1′, h2′ and h3′ will be described hereunder. First, thecontroller 9 obtains the coordinates (x0, y0, z0) for the apex for theheart H and the coordinates (x4, y4, z4) for the base, based on thevolume data V1 for the resting phase. Additionally, a new coordinateaxis (heart length coordinate axis) ζ is set in the direction from theapex to the base, based on this xyz coordinate system. Here, thecoordinate value of the apex is to be ζ=ζ0, and the coordinate value ofthe base is to be ζ=ζ4.

Additionally, it is assumed that coordinate values of intersectionpoints between the cross-sectional positions h1, h2 and h3 for the MPRimages in the resting phase and the heart length coordinate axis ζ arerespectively (x1, y1, z1) (=ζ1), (x2, y2, z2) (=ζ2), and (x3, y3, z3)(=ζ3). These piece of coordinate value information are stored as thecross-sectional-position information D1 for the resting phase.Additionally, the coordinates of the apex for the heart H (x0, y0, z0)(=ζ0), and the coordinates of the base (x4, y4, z4) (=ζ4), for theresting phase are also stored as the cross-sectional-positioninformation D1.

At the time of shift to the stress phase, the user specifies the stressphase mode using the user interface 8. Once the volume data V2 isgenerated in the stress phase, the controller 9 obtains the coordinates(x0′, y0′, z0′) for the apex of the heart H and the coordinates (x4′,y4′, z4′) for the base, based on the volume data V2. Additionally, thecontroller 9 obtains the coordinate value for these coordinates based onthe heart length coordinate axis ζ. At this time, the position of theapex is to be ζ=ζ0′, while the position of the base is to be ζ=ζ4′.

Additionally, the controller 9 obtains the coordinate values for theintersection points (x1′, y1′, z1′) (=ζ1′), (x2′, y2′, z2′) (=ζ2′), and(x3′, y3′, z3′) (=ζ3′), between each of the cross-sectional positionsh1′, h2′ and h3′ for the stress phase and the heart length coordinateaxis ζ, based on the contraction rate α for the heart H and thecoordinate values for the above intersection points in the resting phase(x1, y1, z1) (=ζ1), (x2, y2, z2) (=ζ2), and (x3, y3, z3) (=ζ3). For thecontraction rate α, the predetermined value can be used as describedabove, or it can be obtained at every examination based on the length Land L′ of the heart H for each phase.

An example of a process of obtaining the intersection points will bedescribed hereunder. First, distances Δζ1, Δζ2 and Δζ3 between the apexposition ζ=ζ0 in the resting phase and each of the intersection pointsζ=ζ1, ζ2 and ζ3 are calculated. Next, the contraction rate α ismultiplied to each of the distances Δζ1, Δζ2 and Δζ3: Δζ1′=α×Δζ1,Δζ2′=α×Δζ2, and Δζ3′=α×Δζ3.

Subsequently, the coordinates, which are positioned the distance Δζ1′,Δζ2′ and Δζ3′ away from the apex position ζ=ζ0′ are individuallycalculated for the volume data obtained in the stress phase:ζ1′=ζ0+Δζ1′, ζ2′=ζ0+Δζ2′, and ζ3′=ζ0+Δζ3′ (a direction from the apex tothe base is to defined as a + direction for the heart length coordinateaxis ζ).

Each of the positions ζ1′, ζ2′ and ζ3′ is converted into a coordinatevalue shown in the three-dimensional coordinate system defined in thevolume data. Thus, the coordinate values (x1′, y1′, z1′), (x2′, y2′,z2′) and (x3′, y3′, z3′) for the intersection points between thecross-sectional positions h1′, h2′ and h3′ for the stress phase, and theheart length coordinate axis ζ, can be obtained.

Each of the cross-sectional positions h1′, h2′ and h3′ is set as a planeof a specified direction, such as a plane orthogonal to the heart lengthcoordinate axis ζ. In other words, a direction of the normal line of theplane that forms the respective cross-section a positions h1′, h2′ andh3′ is predetermined. For example, the normal direction is set to beequal to the direction of the heart length coordinate axis ζ. Thecontroller 9 obtains a plane having the normal line and passing throughthe coordinate value (x1′, y1′, z1′), and then sets the plane to thecross-sectional position h1′. The same setting can be performed with thecross-sectional positions h2′ and h3′.

The MPR processor 52 generates image data for the MPR image obtained inthe cross-sectional positions h1′, h2′ and h3′, based on the volume dataobtained in the stress phase. The controller 9 causes the MPR images ofthe stress phase and the MPR images of the resting phase, to bedisplayed side-by-side.

According to this modification example, it is possible to efficientlyperform an examination in the stress phase for stress echocardiography.

Another Modification Example

An example of a case of performing further examination after performingtwo or more examinations in the past will be described hereunder. Theinformation memory 6 stores the cross-sectional-position informationobtained in the respective past examinations. The image data memory 7stores the volume data (and/or the image data for the MPR image)obtained in the respective past examinations. Here, each of thecross-sectional-position information and the volume data areindividually associated with the examination date information showingthe examination date.

In the case of performing a third-time examination and more, thecontroller 9 searches the cross-sectional-position information for theprevious examination (latest examination performed in the past) based onthe examination date information and, based on thecross-sectional-position information, sets the cross-sectional positionfor this-time examination. The MPR processor 52 generates image data forthe MPR image in the relevant cross-sectional position, based on thevolume data obtained in the previous examination.

In many cases, in the examination for observing the time-elapsed changesin biological tissue, this-time examination result and the previousexamination result are comparatively observed. Therefore, according tothis modification example, it is possible to increase the efficiency ofsuch an examination.

Additionally, like the case in which there are two or more stress phasesin the above embodiment, if images are obtained at three or moredifferent dates and times, in the case of comparative observation of theimages of arbitrary two dates and times, the image obtained at theearlier date, out of these two dates and times is equivalent to a “past”image, while the image obtained at the later date is equivalent to a“new” image.

Additionally, it is also possible to comparatively observe images ofthree or more dates and times. In that case, the image obtained at thelatest date, out of these three or more dates and times is equivalent toa “new” image, while the image obtained at each date before that isequivalent to a “past” image.

It should be noted that simultaneous display of the images obtained atthree or more dates and times can be applied to the case of real-timeobservation of images of the biological tissue, and can also be appliedto the case of reviewing the images previously obtained at three or moredates and times.

Second Embodiment

A second embodiment of an ultrasound diagnostic apparatus according tothe present invention will be described hereunder. In the firstembodiment described above, the cross-sectional position for the MPRimage generated from the volume data is pre-stored, and the relevantcross-sectional position is reproduced in a later examination.Meanwhile, in the second embodiment, a scanning position of ultrasoundby an ultrasonic probe is pre-stored, and the ultrasonic scan iscontrolled so that the relevant scanning position is reproduced in alater examination.

[Apparatus Configuration]

FIG. 12 illustrates an example of an ultrasound diagnostic apparatusaccording to the second embodiment. An ultrasound diagnostic apparatus100 has the similar configuration as the ultrasound diagnostic apparatus1 according to the first embodiment. Below, the similar components as inthe first embodiment will be denoted by the same reference numerals.

The information memory 6 stores scanning position information F thatshows an ultrasonic scanning position by the ultrasonic probe 2.Additionally, the image data memory 7 stores image data M such as imagedata for a tomographic image and volume data.

The ultrasound diagnostic apparatus 100 is configured to performoperations that are characteristic of this embodiment, based on acontrol program 92.

[Usage]

The usage of the ultrasound diagnostic apparatus 100 will be describedhereunder. A flow chart shown in FIG. 13 illustrates an example of ausage in the case in which the ultrasound diagnostic apparatus 100 isapplied to a stress echocardiography examination.

Examination in the Resting Phase

First, an examination in the resting phase is performed. At the start,the ultrasonic scan is performed on the heart using the ultrasonic probe2 (S21).

Here, a multi-plane scan of scanning each of a plurality ofcross-sectional positions is performed. For example, a bi-plane scan ofscanning each of two cross-sectional positions, a tri-plane scan ofscanning each of three cross-sectional positions, or the like isperformed (e.g., refer to the Japanese Unexamined Patent ApplicationPublication No. 2004-209247). The multi-plane scan is widely used forreal-time observation of biological tissue, since a series of scan canbe performed in a short time, compared with a three-dimensionalultrasonic scan.

FIGS. 14A and 14B illustrates an example of the multi-plane scan. FIGS.14A and 14B illustrates a scanning mode in the case of viewing thebiological tissue (heart H) from the ultrasonic probe 2. In the bi-planescan shown in FIG. 14A, the ultrasound is scanned along two scanningpositions A1 and A2, which are orthogonal to each other. Additionally,in the tri-plane scan shown in FIG. 14B, the ultrasound is scanned alongthe two scanning positions A1 and A2 orthogonal to each other, and alonga scanning position A3 positioned in the equiangular direction to therespective scanning positions A1 and A2. By way of example, a case ofperforming the bi-plane scan shown in FIG. 14A will be described below.

In the case of an apex approach, a topographic image obtained byscanning along the scanning position A1 becomes an image of an apicaltwo-chamber view. A topographic image obtained by scanning along thescanning position A2 becomes an image of an apical four-chamber view.These images are tomographic images whose cross sections are each aplane formed by the scanning direction of the ultrasound along each ofthe scanning positions A1 and A2 and the traveling direction of theultrasound.

The reception results arising from the ultrasonic scan (bi-plane scan)in Step S21 are transmitted to the B-mode processor 41 via thetransceiver 3. At this time, the reception results arising from scanningthe scanning position A1 and the reception results arising from scanningthe scanning position A2 are alternatively transmitted to the B-modeprocessor 41.

The B-mode processor 41 alternatively generates image data of thetomographic image of the apical two chamber (apical two-chamber view)and the image data of the tomographic image of the apical four chamber(apical four-chamber view), based on these reception results (S22).

The controller 9 causes the display part 81 to display the apicaltwo-chamber view and the apical four-chamber view (S23). These imagesare respectively displayed, for example, in the display ranges 1004 and1005 of the tomographic-image-comparing screen 1000 shown in FIG. 5.Additionally, the controller 9 causes each of the apical two-chamberview and the apical four-chamber view, to be displayed and updated insynchronization with a repetition interval of scanning for each of thescanning positions A1 and A2.

A user adjusts the manner of placement of the ultrasonic probe 2 on thesubject as needed so that the apical two-chamber view and the apicalfour-chamber view are appropriately displayed (S24).

Once the apical two-chamber view and apical four-chamber view aredisplayed appropriately, the user performs an operation for storing theimage data through the operation part 82 (S25). After receiving thisoperation, the controller 9 stores, in the image data memory 7, theimage data (volume data) M1 for the resting phase including the imagedata of the apical two-chamber view (motion data) and the apicalfour-chamber view (motion data) (S26).

Additionally, the controller 9 stores, in the information memory 6, thescanning position information F1 showing the scanning position of theultrasound by the ultrasonic probe 2, which is obtained when the imagedata M1 is obtained (S27).

The ultrasonic probe 2 comprises a plurality of ultrasonic transducerstwo-dimensionally arranged as described above. The transceiver 3 drivesand controls the respective ultrasonic transducers based on a scanningcontrol signal from the controller 9, thereby scanning an ultrasonicbeam in a desired scanning position (in this case, the scanningpositions A1 and A2).

The scanning position information F1 is generated by the controller 9based on the scanning control signal. The scanning position informationF1 includes position information showing the scanning positions A1 andA2. This position information is information showing, for example, ascanning direction and scanning angle of the ultrasound by theultrasonic probe 2. This is the end of the examination in the restingphase.

Examination in a Stress Phase

Subsequently, the examination in the stress phase will be performed. Forthat, the user first causes the display part 81 to display a screen thatdisplays the topographic images of the stress phase (S28). This screenis, for example, the tomographic-image-comparing screen 2000 shown inFIG. 6.

The controller 9 reads out the image data M1 for the resting phase, andcauses the display ranges 2001 and 2002 to display the apicaltwo-chamber view and the apical four-chamber view obtained in theresting phase, respectively (S29).

Additionally, the controller 9 reads out the scanning positioninformation F1 for the resting phase, generates the scanning controlsignal for scanning the ultrasound along the scanning positions A1 andA2 shown in the scanning position information F1, and then transmitsthem to the transceiver 3. Once the user starts the ultrasonic scan inorder to obtain the images of the stress phase, the transceiver 3 drivesthe respective ultrasonic transducers of the ultrasonic probe 2, basedon this scanning control signal. This makes it possible to perform theultrasonic scan along the same scanning positions A1 and A2 as in theresting phase (S30).

The reception results by the ultrasonic probe 2 are transmitted to theB-mode processor 41 through the transceiver 3. The B-mode processor 41alternatively generates image data for the tomographic images takenalong the scanning positions A1 and A2, based on this reception result(S31).

The controller 9 causes the respective display ranges 2004 and 2003 todisplay the tomographic image taken along the scanning position A1 andthe tomographic image taken along the scanning position A2, based onthese image data (S32). Each of the displayed images is a moving imagethat is updated at specified time intervals.

The user adjusts the manner of placement of the ultrasonic probe 2 onthe subject as needed so that the cross-sectional position for thetomographic image displayed in the display range 2003 is the same as thecross-sectional position for the apical four-chamber view displayed inthe display range 2001 (S33). The user may ad just the manner ofplacement of the ultrasonic probe 2 so that the cross-sectional positionfor the tomographic image displayed in the display range 2004 matchesthe cross-sectional position for the apical two-chamber view displayedin the display range 2002.

As described above, once one cross-sectional position is matched,another cross-sectional position is also matched. One cross-sectionalposition is matched, which results in that the apical four-chamber viewfor the stress phase in the (approximate) same cross-sectional positionas the apical four-chamber view for the resting phase is displayed inthe display range 2003, and the apical two-chamber view for the stressphase in the (approximate) same cross-sectional position as the apicaltwo-chamber view for the resting phase is displayed in the display range2004.

Once the stress phase image and the resting phase image are displayed bymatching their positions, the user performs an operation for requestingstorage of the image data (S34). Upon reception of this operation, thecontroller 9 stores, in the image data memory 7, the image data for thestress phase (volume data) M2 including the image data for the apicalfour-chamber view and the image data for the apical two-chamber view,which are real-time generated at the specified frame rate respectively(S35).

Additionally, the controller 9 stores, in the information memory 6, thescanning position information F2 showing the scanning position of theultrasound obtained when the image data M2 is obtained.

If there is a next phase (S37; Y), the above steps S30 to S36 will berepeated. In this next phase, the MPR image for a phase other than theresting phase, such as the previous phase, can be displayed with the MPRimage for the relevant next stress phase. After observation for allphases is completed (S37; N), the examination in the stress phase are tobe ended.

[Actions and Advantageous Effects]

Actions and advantageous effects of the ultrasound diagnostic apparatus100 are described. When obtaining the image data for the tomographicimages of biological tissue such as a heart (in this case, the apicalfour-chamber view and the apical two-chamber view), the ultrasounddiagnostic apparatus 100 stores, in the information memory 6, thescanning position information F showing the scanning position of theultrasonic scan performed by the ultrasonic probe in order to obtain thetomographic image. Subsequently, when obtaining the image data for newtomographic image of this biological tissue, the ultrasound diagnosticapparatus 100 performs the ultrasonic scan by reproducing the scanningposition shown in the scanning position information F obtained when theimage data of the tomographic image has been obtained in the past, andthen displays the new tomographic image obtained thereby and the pasttomographic image side-by-side.

In particular, in the case of stress echocardiography, the ultrasounddiagnostic apparatus 100 can display the tomographic image in real-time,while performing the ultrasonic scan for this-time phase, based on thescanning position information F for the past phase examination.

According to the ultrasound diagnostic apparatus 100, it is possible toautomatically obtain the tomographic image at almost the samecross-sectional position as the tomographic image observed in the pastexamination, in the examination (stress echocardiography, an observationof the clinical course, and a preoperative/postoperative observation)for observing the time-elapsed changes in biological tissue. This makesit possible to easily obtain the tomographic image in the samecross-sectional position of the biological tissue. Additionally, sincethis embodiment is configured to perform the multi-plane scan, thereal-time observation of the biological tissue can be preferablyperformed.

Additionally, according to the ultrasound diagnostic apparatus 100, thetomographic image obtained in the past examination and the tomographicimage obtained in the new examination are displayed side-by-side, sothat it possible to easily perform a comparative observation of theseimages.

Additionally, the user can match the cross-sectional position of the newtomographic image with the cross-sectional position of the pasttomographic image by simply adjusting the manner of placement of theultrasonic probe 2, as needed. This makes it possible to easily performan examination such as a stress echocardiograph examination forobserving the time-elapsed changes in biological tissue. It is alsopossible to shorten the examination time.

Furthermore, according to the ultrasound diagnostic apparatus 1, asshown in FIG. 6, it is possible to simultaneously display a plurality ofpairs of the past tomographic image and the new tomographic image whosecross-sectional positions are matched with each other. That enables theuser to perform a comprehensive diagnosis, during a comparativeobservation of the images of various cross-sectional positions of thebiological tissues.

[Another Usage]

The following usage can be performed when the ultrasound diagnosticapparatus 100 shown in FIG. 12 is used. This usage is to use both anultrasonic multi-plane scan and a three-dimensional scan with theultrasound. The case in which this usage is applied to stressechocardiography will be herein described.

Examination in the Resting Phase

In the resting phase examination, firstly, the bi-plane scan isperformed as in the aforementioned usage, and the image data M1including the image data of the apical four-chamber view and the imagedata of the apical two-chamber view for the heart is obtained andstored. Additionally, the scanning position information F1 showing thescanning positions A1 and A2 of the ultrasound when these sets of imagedata have been stored.

Subsequently, as in the first embodiment, the volume data for the heartis generated, and the image data for the MPR image is generated. Thegenerated MPR images (e.g., the MPR images G1, G2 and G3 for theshort-axis view of the left ventricle, the MPR image G4 for the apicalfour-chamber view, and the MPR image G5 for the apical two-chamber view)are displayed on the tomographic image display screen 1000 (refer toFIG. 5).

The user adjusts the manner of placement of the ultrasonic probe 2 asneeded to display the MPR image for the appropriate cross-sectionalposition. Then, the volume data V1 and the image data for the MPR imagein the resting phase are stored (refer to FIG. 1). This is the end ofthe examination in the resting phase.

Examination in a Stress Phase

In the stress phase examination, at first, the apical four-chamber viewand the apical two-chamber view in the resting phase are displayedalongside with the apical four-chamber view and the apical two-chamberview in the stress phase, as in the abovementioned usage. Thesetomographic images are displayed on the tomographic-image-comparingscreen 2000.

At this time, the tomographic images in the stress phase are obtained bythe bi-plane scan based on the scanning position information F1 for theresting phase.

The user adjusts the manner of placement of the ultrasonic probe 2 asneeded so as to match the cross-sectional position of the tomographicimage in the stress phase with the cross-sectional position of thetomographic image in the resting phase.

Next, the scanning mode of the ultrasound performed by the ultrasonicprobe 2 is switched into a three-dimensional scan. Then, the volume datafor the stress phase is generated, and the image data for the MPR imageis generated. After that, the MPR image in the stress phase and the MPRimage in the resting phase are displayed side by side. These MPR imagesare displayed on, for example, the tomographic-image-comparing screens2000 and 3000. Alternatively, it is possible to merely store the volumedata without generating and displaying the MPR images.

The user adjusts the manner of placement of the ultrasonic probe 2 asneeded in order to match the cross-sectional positions of the MPRimages. Then, user stores the volume data V2 and the image data for theMPR image in the stress phase. Several stress phases are repeated inaccordance with the protocol types. This is the end of the examinationin the stress phase.

According to this usage, it is possible to match the positions of theimages in each phase by using the position of the multi-plane scan.Additionally, it is possible to perform the three-dimensional scan afterthe positions are matched and obtain the volume data and the MPR images.Consequently, it is possible to easily match the positions of theimages. Additionally, it is possible to easily obtain the volume dataand the MPR images whose positions have been matched. Furthermore, thereis a merit that an examination can be performed in real time with goodtime resolution.

Medical Image-Processing Apparatus

A medical image-processing apparatus according to the present inventionwill be described hereunder. The medical image-processing apparatuscomprises any computer capable of reading data generated by anultrasound diagnostic apparatus. An example of the medicalimage-processing apparatus is a computer connected to the ultrasounddiagnostic apparatus. Additionally, another example of the medicalimage-processing apparatus is a computer connected to a database such asa PACS (Picture Archiving and Communication System) that stores imagedata of ultrasonic images.

FIG. 15 illustrates an example of the medical image-processing apparatusaccording to the present invention. In FIG. 15, components that operatesimilarly to those in the first embodiment are denoted by the samereference numerals.

A medical image-processing apparatus 200 comprises the image processor5, the information memory 6, the image data memory 7, the user interface8, and the controller 9, in the same manner as the ultrasound diagnosticapparatus 1 shown in FIG. 1.

The image processor 5 functions as an example of an “image datagenerator” in the present invention. The information memory 6 functionsas an example of a “memory” in the present invention. The display part81 functions as an example of a “display part” in the present invention.Additionally, the controller 9 functions as an example of a “controller”in the present invention.

This medical image-processing apparatus 200 is connected to anultrasound diagnostic apparatus 300 and a medical image database 400 viaa network N such as a LAN (local area network). For data communicationvia the network N, protocol communication such as a DICOM is used. Thecontroller 9 comprises a network card for performing data communicationvia the network N. The ultrasound diagnostic apparatus 300 has anultrasonic probe capable of performing three-dimensional scan.

An example of an operation performed by the medical image-processingapparatus 200 will be described hereunder. The image data for theultrasonic image is inputted from the ultrasound diagnostic apparatus300 or the medical image database 400 to the medical image-processingapparatus 200.

In the case in which the image data for the B-mode images (tomographicimages) are inputted, the volume data generator 51 generates the volumedata based on these image data. The MPR processor 52 generates imagedata for the MPR image, based on this volume data, as in the firstembodiment.

On the other hand, in the case in which the inputted image data isvolume data, the MPR processor 52 generates image data for the MPR imagebased on this volume data. The volume data and the image data for theMPR image are stored in the image data memory 7 by the controller 9.

An example of a usage of the medical image-processing apparatus 200 willbe described hereunder. First, data for a comparative observation isobtained from the ultrasound diagnostic apparatus 300 or the medicalimage database 400. This data includes the image data for the ultrasonicimages obtained at a plurality of examination dates.

In the case in which the image data is obtained from the ultrasonicimage apparatus 300, the image data obtained by the ultrasounddiagnostic apparatus 300 is inputted to the medical image-processingapparatus 200 at the specified timing.

Alternatively, in the case in which it is obtained from the medicalimage database 400, for example, the controller 9 causes the displaypart 81 to display a patient list. The user selects and specifies adesired patient from this list. The controller 9 transmits, to themedical image database 400, the patient identification information suchas a patient ID of the specified patient. The medical image database 400searches the image data for the ultrasonic image of the relevantpatient, using this patient identification information as a search key,and transmits them to the medical image-processing apparatus 200. It isalso possible to configure so as to specify the examination date, searchthe image data for the specified examination date, and input it to themedical image-processing apparatus 200.

In the case in which the image data that has been externally input isthe image data for the B-mode image, the medical image-processingapparatus 200 generates the volume data based on that, and stores it inthe memory 7. Alternatively, in the case in which the image data thathas been externally input is the volume data, that is directly stored inthe data memory 7.

As described above, the volume data V1 and V2 are stored in the imagedata memory 7 as shown in FIG. 15. Here, the volume data V1 correspondsto the first examination date in an observation of the clinical course,while the volume data V2 corresponds to the second examination date.

At first, the user causes the display part 81 to display the MPR imagebased on the volume data V1. At this time, the user set thecross-sectional position by performing the specified operation. In thecase in which the cross-sectional position that has been set is ashort-axis view of the left ventricle, the controller 9 causes displayranges 3001 to 3003 of a tomographic-image-comparing screen 3000, torespectively display MPR images G1 to G3 of the short-axis view of theleft ventricle.

In the case in which the cross-sectional position having been set is anapical four-chamber view and an apical two-chamber view, the MPR imagesG4 and G5 corresponding thereto are displayed in atomographic-image-comparing screen 2000.

The controller 9 generates the cross-sectional-position information D1showing the set cross-sectional position, and stores them in theinformation memory 6.

Here, in the case in which observation of the image obtained on thefirst examination date was performed in the past, and a comparativeobservation between the images obtained on the first and the secondexamination date is performed for this time, it is possible, at the pasttime-point for setting the cross-sectional position of the MPR image, togenerate the cross-sectional-position information D1 showing thiscross-sectional position, and store them in the information memory 6.

The MPR processor 52 generates image data for the MPR image in therelevant cross-sectional position, based on the cross-sectional positionshown in the cross-sectional-position information D1, and the volumedata V2. This MPR image means an MPR image for the relevantcross-sectional position obtained on the second examination date.

The controller 9 causes the display part 81 to display the MPR imageobtained on the second examination date together with the MPR imageobtained on the first examination date. Thus, for example, the displayranges 3001 to 3003 of the tomographic-image-comparing screen 3000respectively displays a short-axis view of the left ventricle G1 to G3obtained on the first examination date, and the display ranges 3004 to3006 of the tomographic-image-comparing screen 3000 respectivelydisplays a short-axis view of the left ventricle G1′ to G3′ obtained onthe second examination date.

The user can accordingly changes the cross-sectional positions of theshort-axis view of the left ventricles G1′ to G3′ as needed, in order tomatch them with the cross-sectional positions of the short-axis view ofthe left ventricles G1 to G3. On the contrary, the user can accordinglychanges the cross-sectional positions of the short-axis view of the leftventricle views G1 to G3, in order to match them with thecross-sectional positions of the short-axis view of the left ventricleviews G1′ to G3′.

This medical image-processing apparatus 200 is capable of automaticallymatching the cross-sectional positions of the tomographic images whendisplaying the tomographic images that have been respectively obtainedat different dates, in the case of the examination for observing thetime-elapsed changes in biological tissue. This makes it possible toeasily obtain the tomographic image in the same cross-sectional positionof the biological tissue.

The ultrasound diagnostic apparatus 200 is capable of displaying thetomographic images obtained on the different examination side-by-side inthe condition in which the cross-sectional positions thereof arematched, which makes it possible to easily comparatively observe theseimages.

Additionally, the user can match the cross-sectional positions of thetomographic images obtained on different dates by simply adjusting themanner of placement of the ultrasonic probe 2. This makes it possible toeasily perform an examination such as a stress echocardiography forobserving the time-elapsed changes in biological tissue. It is alsopossible to shorten the examination time.

The medical image-processing apparatus 200 is capable of applying anymodification examples described in the first embodiment as needed.

Program

A program according to the present invention will be describedhereunder. The programs 91 and 92 described in the first embodiment andsecond embodiment, as well as the control program 91 for the medicalimage-processing apparatus 200, correspond to an example of a programaccording to the present invention.

The control programs 91 and 92 cause a computer to execute the processesdescribed in the embodiments above and the modification examplesthereof. The control programs 91 and 92 are stored beforehand in astorage unit such as a hard disk drive incorporated into the computer.Additionally, it is also possible to make a configuration so that thecontrol programs 91 and 92 are stored beforehand on a server or the likeon a network such as a LAN and then the computer reads this out forexecution.

The control programs 91 and 92 can be stored on an arbitrarycomputer-readable storage media. Examples of this storage media include,an optical disk, a magneto-optical disk (e.g., CD-ROM, DVD-RAM, DVD-ROM,MO), a magnetic storage medium (e.g., hard disk, Floppy® disk, ZIPdrive), and a semiconductor memory.

Another Modification Example

In the embodiments described above, stress echocardiography examinationperformed by an apex approach has been described, but examinations usingthe present invention can be applied to an arbitrary approach, such as aparasternal approach, an approach via the liver, and an approach fromthe neck.

Here, “approach” refers to the manner of placement of an ultrasonicprobe for obtaining an image of biological tissue, or in other words, atransmission direction (reception direction) of ultrasound to thebiological tissue. By taking different approaches, images in which thebiological tissue from different directions is viewed can be obtained.

Two or more approaches may be combined for the actual examination. Thepreferred configuration for the case of performing the examination(stress echocardiography) in a combination of the apex approach and theparasternal approach will be described with reference to FIG. 16.

In stress echocardiography shown in FIG. 16, each of the resting phase,stress phase 1, stress phase 2 . . . , and stress phase K (K is aninteger that is equal to or more than 1) is configured to be performedwith examination via the apex approach and an examination via theparasternal approach.

The control program 91 (or the control program 92) described in theembodiments above preliminarily includes protocol for the apex approachand protocol for the parasternal approach. The case of using theultrasound diagnostic apparatus 1 (refer to FIG. 1) in the firstembodiment will be described hereunder. It should be noted that the samecould be configured with the abovementioned medical image-processingapparatus 200.

In the resting phase, a user specifies an apex approach by operating theoperation part 82. The controller 9 selects protocol used for the apexapproach in the control program 91 and causes the ultrasound diagnosticapparatus 1 to execute the following process.

The user places an ultrasonic probe 2 on the body surface adjacent to anapex of the heart for performing a three-dimensional scan viaultrasound. That enables the MPR image to be displayed on the displaypart 81. The user observes this MPR image. The controller 9 mutuallyassociates the image data (volume data, etc. for imaging performed bythe apex approach in the resting phase, the cross-sectional-positioninformation showing the cross-sectional position of the observed image,and the identification information for the approach (e.g.,identification information in the protocol) and then stores them. Here,the image data is stored in the image data memory 7, and thecross-sectional-position information and identification information forthe approach are stored in the information memory 6. The identificationinformation for the approach should be set beforehand.

Next, the user specifies a parasternal approach by operating theoperation part 82. The controller 9 selects protocol used for theparasternal approach in the control program 91, and causes theultrasound diagnostic apparatus 1 to execute the following process.

The user places the ultrasonic probe 2 on the body surface adjacent to aparasternal part for performing a three-dimensional scan via ultrasoundand then observes the image (MPR image) displayed on the display part81. The controller 9 mutually associates the image data (volume data,etc.) for imaging performed by the parasternal approach for the restingphase, the cross-sectional-position information showing thecross-sectional position of the observed image, and the identificationinformation for the approach and then stores these in the informationmemory 6 and in the image data memory 7.

Subsequently, in the stress phase 1, a user specifies the apex approachby operating the operation part 82. The user places the ultrasonic probe2 on the body surface adjacent to an apex part for performing athree-dimensional scan via ultrasound and then observes the image (MPRimage) displayed on the display part 81.

Here, the controller 9 obtains, from the information memory 6, thecross-sectional-position information associated with the identificationinformation for the specified approach (apex approach). The MPRprocessor 52 generates image data for the MPR image obtained by the apexapproach in the stress phase 1, based on the cross-sectional positionshown this cross-sectional-position information, and the volume datagenerated by the volume data generator 51.

The controller 9 causes the display part 81 to display the MPR imagebased on this image data together with the MPR image obtained by theapex approach in the resting phase. The user adjusts the manner ofplacement of the ultrasonic probe 2 so that the cross-sectional positionof the MPR image for the stress phase 1 matches the cross-sectionalposition of the MPR image for the resting phase.

This makes it possible to compare the conditions in the (approximate)same cross-sectional positions in the resting phase and in the stressphase 1. The volume data, the cross-sectional-position information, andthe identification information for the protocol for the apex approach inthe stress phase 1 are mutually associated and then stored in theinformation memory 6 and in the image data memory 7.

Next, the user specifies the parasternal approach by operating theoperation part 82. The user places the ultrasonic probe 2 on the bodysurface adjacent to the parasternal part for performing athree-dimensional scan via ultrasound and then observes the image (MPRimage) displayed on the display part 81.

Here, the controller 9 obtains, from the image data memory 7, thecross-sectional-position information associated with the identificationinformation for the specified approach (parasternal approach). The MPRprocessor 52 generates image data for the MPR image obtained by theparasternal approach in the stress phase 1, based on the cross-sectionalposition shown in this cross-sectional-position information, and thevolume data generated by the volume data generator 51.

The controller 9 causes the display part 81 to display the MPR imagebased on this image data together with the MPR image obtained by theparasternal approach in the resting phase. The user adjusts the mannerof placement of the ultrasonic probe 2 so that the cross-sectionalposition of the MPR image for the stress phase 1 matches thecross-sectional position of the MPR image for the resting phase.

This makes it possible to compare the conditions in the (approximate)same cross-sectional positions in the resting phase and in the stressphase 1. The volume data, the cross-sectional-position information, andthe identification information for the protocol obtained in theparasternal approach for the stress phase 1 are mutually associated andthen stored in the information memory 6 and in the image data memory 7.

With respect to each stress phase 2 to K, the same process as the stressphase 1 will be performed. In other words, in the case of the apexapproach for each stress phase 2 to K, the MPR image obtained by theapex approach for the resting phase (or the stress phase before therelevant stress phase) as well as the MPR image for the relevant stressphase in the (approximate) same cross-sectional position as this MPRimage are displayed. The volume data, the cross-sectional-positioninformation, and the identification information for the protocolobtained in the apex approach for the relevant stress phase are mutuallyassociated and then stored in the information memory 6 and in the imagedata memory 7.

Meanwhile, in the case of the parasternal approach for each stress phase2 to K, the MPR image obtained by the parasternal approach for theresting phase (or the stress phase before the relevant stress phase) aswell as the MPR image for the relevant stress phase in the (approximate)same cross-sectional position as this MPR image are displayed. Thevolume data, the cross-sectional-position information, theidentification information for the protocol obtained in the parasternalapproach for the relevant stress phase are mutually associated and thenstored in the information memory 6 and in the image data memory 7.

By using the configuration as described above, even if two or more typesof approaches are taken in each phase (or each examination date), it ispossible to easily obtain the tomographic images in the samecross-sectional positions with respect to each approach. It is alsopossible to improve the simplification and time shortening of theexamination.

The configuration for the relevant modification example can be appliedto the above-mentioned second embodiment of the ultrasound diagnosticapparatus 100 (refer to FIG. 12). More specifically, first, the scanningposition information of the ultrasonic probe 2 for biological tissuesuch as a heart is stored with respect to each of two or moreapproaches. Then, with respect to each of the two or more approaches,the ultrasonic probe 2 is controlled so that the ultrasound istransmitted to the scanning position shown in the scanning positioninformation stored when the relevant approach was taken in the past.Additionally, image data for the new tomographic image is generated,based on the reception result of the ultrasound transmitted to thisscanning position and then the past tomographic image and the newtomographic image in the relevant approach are displayed side-by-side.

According to this configuration, even if two or more types of approachesare taken in each phase (date), it will be possible to easily obtaintomographic images for the same cross-section of the biological tissuefor each approach. It is a so possible to improve simplification andtime shortening of the examination.

The case of taking two approaches in each phase has been describedherein, but even in the case of taking three or more approaches in eachphase, the same process can be performed for each approach.

Additionally, it is not necessary for all approaches for each phase tobe taken, and only some of the approaches may be selectively taken. Forexample, the user may select the approach.

Furthermore, the present invention can be accordingly applied toexaminations for biological tissues other than a heart.

What is claimed is:
 1. An ultrasound diagnostic apparatus comprising: anultrasonic probe configured to transmit ultrasound whilethree-dimensionally scanning, and receive ultrasound reflected by abiological tissue; an image data processor configured to generate imagedata of a tomographic image of biological tissue based on receptionresults of ultrasound and to generate image data of an MPR (Multi-PlanarReconstruction) image based on the volume data; a memory configured tostore cross-sectional-position information showing a cross-sectionalposition of the tomographic image with regard to a first image data of afirst MPR image generated by the image data processor taken at a firsttime; a display; and a controller configured to control the image dataprocessor so as to, when a second image data representing a tomographicimage of the biological tissue is generated by the image data processorbased on reception results of new ultrasound taken at a second time,cause the display to display the second image data of a second MPR imagehaving a cross sectional position identical to a cross sectionalposition of the first image data of the first MPR image.
 2. Theultrasound diagnostic apparatus according to claim 1, further comprisinga user interface, wherein: the image data processor is configured togenerate the first image data and the second image data, each of whichis an MPR image of the cross-sectional position designated by the userinterface; and the controller is configured to cause the display todisplay the first image data and the second image data side by side. 3.The ultrasound diagnostic apparatus according to claim 1, furthercomprising a user interface configured to change an imaging mode thatincludes a scanning pattern of ultrasound by the ultrasonic probe and agenerating pattern of image data of an MPR image by the image dataprocessor, wherein: the memory is configured to store thecross-sectional-position information so as to be associated with animaging mode used when image data of an MPR image has been generated;and when an imaging mode is changed by the user interface, thecontroller is configured to use a cross-sectional position shown incross-sectional-position information associated with the imaging modeafter the change, of cross-sectional-position information stored in thememory.
 4. The ultrasound diagnostic apparatus according to claim 1,wherein: the first image data and the second image data comprise imagedata of each of MPR images of two or more cross-sectional positionsdifferent from each other; the memory is configured to storecross-sectional-position information including a cross-sectionalposition of each of the two or more MPR images included in the firstimage data; and the controller is configured to cause the display todisplay side by side, two or more MPR images included respectively inthe first and second image data.
 5. The ultrasound diagnostic apparatusaccording to claim 1, wherein the controller causes the display todisplay a past tomographic image and a new tomographic image side byside.
 6. The ultrasound diagnostic apparatus according to claim 1,wherein the cross-sectional-position information indicates a position ofa tomographic image on a scanning region of three-dimensional scanningby the ultrasonic probe.